Near-infrared (NIR)-to-NIR upconverting NaY(Gd)F₄:Tm³⁺,Yb³⁺ paramagnetic nanoparticles (NPs) are efficiently detected by NIR imaging techniques. As they contain Gd³⁺ ions, they also provide efficient “positive” contrast in magnetic resonance imaging (MRI). Water-dispersible small (≈25 nm, “S-”) and ultrasmall (<5 nm diam., “US-”) NaY(Gd)F₄:Tm³⁺,Yb³⁺ NPs are synthesized by thermal decomposition and capped with citrate. The surface of citrate-coated US-NPs shows sodium depletion and high Gd elemental ratios, as confirmed by a comparative X-ray photoelectron spectroscopy (XPS)/neutron absorption analysis study. US-NaGd_0.745F₄:Tm_0.005,Y_b0.25 NPs have hydrodynamic diameters close to that measured by TEM, with the lowest relaxometric ratios (r₂/r₁ = 1.18) reported for NaGdF₄ nanoparticle suspensions (r₁ = 3.37 mM⁻¹ s⁻¹ at 1.4 T and 37 °C). Strong relaxivity peaks in the range of 20 (0.47 T) - 300 MHz (7.05 T) are revealed in nuclear magnetic resonance dispersion profiles, with high r₂/r₁ ratios at increasing field strengths for S-NPs. This indicates the superiority of US-NPs over S-NPs for achieving high positive contrast at clinical MRI field strengths. I.-v. injected citrate-coated US-NPs evidence long blood retention times (>90 min) in mice. Biodistribution studies (48 h, 8 d) show elimination through the reticuloendothelial and urinary systems, similarly to other citrate-capped US-NP systems. In summary, upconverting NaY(Gd)F₄:Tm³⁺,Yb³⁺ nanoparticles have promising luminescent, relaxometric and blood-retention properties for dual MRI/optical imaging.

Lanthanide-doped sodium gadolinium fluoride upconverting nanoparticles are shown to efficiently decrease the relaxation time of protons in aqueous media and provide a positive contrast in MRI applications. In particular, ultrasmall nanoparticles that are less than 5 nm in diameter are shown to have the lowest relaxometric ratios reported to date and a very strong vascular enhancement for times of at least 90 min in the mouse model.

Design and construction of multifunctional nanoparticles for effective delivery and therapeutic application remains a challenging task. It is desirable that nanoparticles can overcome multiple biological barriers and reach specific cellular locations to achieve maximum therapeutic effects. This aim often requires the fine tuning of nanoparticles' chemical and physical properties, as well as better understanding of their interaction with live cells. A peptide-modified gold–nanoparticle platform is designed, which consists of a 20-nm gold core stabilized with a layer of biotinylated CALNN-based peptides and a further layer of tetrameric streptavidins for functionalization with biotinylated molecules. The nanoassembly undergoes an efficient dynamin-dependent and caveolae-mediated endocytosis pathway, and displays highly specific localization to mitochondria, organelles of great therapeutic importance. When functionalized with a cytotoxic peptide (KLA: (KLAKLAK)₂), the KLA-anchored nanoassembly exhibits dramatically enhanced anticancer activity, thousands of times stronger than that of the free KLA peptide, likely because of its improved cell entry efficiency, mitochondria-specific delivery, and the polyvalent effect of the nanoassembly. The study opens up the possibility of developing mitochondria-targeted nanomedicines.

A multifunctional nanoarchitecture with ordered molecular structures is designed and constructed as a platform for multiplexed surface biofunctionalization. The nanoassembly enters cells via caveolae-dependent endocytosis and specifically targets mitochondria. Upon cytotoxic peptide modification, the nanoassembly exhibits dramatically enhanced anticancer activities.

Versatile nanocarrier systems facilitating uptake of exogenous proteins are highly alluring in evaluating these proteins for therapeutic applications. The self-assembly of an efficient nano-sized protein transporter consisting of three different entities is presented: A streptavidin protein core functioning as an adapter, second generation polyamidoamine dendrons for facilitating cell uptake as well as two different therapeutic proteins (tumor suppressor p53 or pro-apoptotic cytochrome c as cargo). Well-defined dendrons containing a biotin core are prepared and display no cytotoxic behavior upon conjugation to streptavidin. The integration of biotinylated human recombinant p53 (B-p53) into the three component system allows excellent internalization into HeLa, A549 and SaOS osteosarcoma cells monitored via confocal microscopy, immunoblot analysis and co-localization studies. In addition, the conjugation of B-p53 to dendronized streptavidin preserves its specific DNA-binding in vitro, and its delivery into SaOS cells impairs cell viability with concomitant activation of caspases 3 and 7. The versatility of this system is further exhibited by the significant enhancement of the pro-apoptotic effects of internalized cytochrome c which is analyzed by flow cytometry and cell viability assays. These results demonstrate that the “bio-click” self-assembly of biotinylated dendrons and proteins on a streptavidin adapter yields a stable supramolecular complex. This efficient bionanotransporter provides an attractive platform for mediating the delivery of functional proteins of interest into living mammalian cells in a facile and rapid way.

A versatile and efficient multidomain delivery system facilitating the cell uptake of the proteins p53 and Cytochrome C is obtained by supramolecular assembly. Such nanotransporters contain a streptavidin protein core functioning as a bio-adapter, second generation polyamidoamine dendrons for cell uptake as well as a therapeutic protein as cargo. The delivery and functional activity of tumor suppressor p53 or pro-apoptotic cytochrome c are studied in detail.

Glioblastoma multiforme (GBM) is the most common and malignant form of primary brain tumors in human. Small molecular magnetic resonance imaging (MRI) contrast agents are used for GBM diagnosis. However, conventional contrast agents have several limitations, such as low T₁ relaxivity, short circulation half lives and absence of tumor targeting. Herein, we develop an upconversion nanoprobe labeled with Gd³⁺-DOTA and RGD (UCNP-Gd-RGD) for dual-modality imaging of glioblastoma. The preparation of UCNP-Gd-RGD starts with amine-functional upconversion nanoparticle core, followed by PEGylation, Gd³⁺DOTA conjugation and RGD labeling. The obtained UCNP-Gd-RGD has improved colloidal stability and reduced cytotoxicity compared with the UCNP core counterpart. Meanwhile, UCNP-Gd-RGD shows strong upconversion luminescence in deep-red region and three times enhancement of T₁ relaxivity over Gd³⁺DOTA. Due to the recognition between UCNP-Gd-RGD and integrin α_vβ₃ receptors, the nanoprobe specifically binds to U87MG cells, as evidenced by confocal microscopy and quantified by ICP-MS. Furthermore, UCNP-Gd-RGD demonstrates a preferential retention in subcutaneous U87MG tumor xenograft as shown in both in vivo upconversion fluorescence/MR imaging studies and ex vivo analysis. UCNP-Gd-RGD, conjugated with numerous RGD peptide and T₁ contrast enhancing molecules, is promising for MR imaging of glioblastoma and delineating the tumor boundary before surgery. In addition, NIR-to-red upconversion characteristic of UCNP-Gd-RGD facilitates its potential intra-operative use for fluorescence-guided tumor resection.

A peptide-labeled paramagnetic/upconversion nanoprobe (UCNP-Gd-RGD) is designed and synthesized. It demonstrates high specificity towards U87MG cells and preferential retention in subcutaneous U87MG tumors. The tumor boundary delineation is successfully achieved through in vivo upconversion fluorescence and MRI studies. This dual-modal nanoprobe holds the potentials in preoperative MR imaging and intra-operative fluorescence-guided surgery

Herein, a pH stimuli-responsive vehicle for intracellular drug delivery using CeO₂ capped mesoporous silica nanoparticles (MSN) is reported. β-Cyclodextrin-modified CeO₂ nanoparticles could cap onto ferrocene-functionalized mesoporous silica through host–guest interactions. After internalization into A549 cells by a lysosomal pathway, the ferrocenyl moieties are oxidized to ferrocenium ions by CeO₂ lids, which could trigger the uncapping of the CeO₂ and cause the drugs release. Because of the pH-dependent toxicity, the CeO₂ here behaves as a multi-purpose entity that not only acts as a lid but also exhibits a synergistic antitumor effect on cancer cells. Meanwhile, the cell protective effect of CeO₂ nanoparticles alone is demonstrated, which ensures that the dissolved CeO₂ nanoparticles can be non-toxic to normal cells.

Herein, a nanoceria-triggered intracellular drug delivery platform using β-CD@CeO₂-capped Fc-MSN is reported. CeO₂ has different enzyme-mimetic activity at different pH conditions. It can be a capping agent and an antioxidant cell protector at physiological pH condition, while at low pH conditions, such as in lysosome, it triggers self-uncapping and has synergetic anticancer effect.

Silk has traditionally been used as a suture material because of its excellent mechanical properties and biocompatibility. These properties have led to the development of different silk-based material formats for tissue engineering and regenerative medicine. Although there have been a small number of studies about the use of silk particles for drug delivery, none of these studies have assessed the potential of silk to act as a stimulus-responsive anticancer nanomedicine. This report demonstrates that an acetone precipitation of silk allows the formation of uniform silk nanoparticles (98 nm diameter, polydispersity index 0.109), with an overall negative surface charge (–33.6 ± 5.8 mV), in a single step. Silk nanoparticles are readily loaded with doxorubicin (40 ng doxorubicin/μg silk) and show pH-dependent release (pH 4.5≫ 6.0 > 7.4). In vitro studies with human breast cancer cell lines demonstrates that the silk nanoparticles are not cytotoxic (IC₅₀ > 120 μg mL⁻¹) and that doxorubicin-loaded silk nanoparticles are able to overcome drug resistance mechanisms. Live cell fluorescence microscopy studies show endocytic uptake and lysosomal accumulation of silk nanoparticles. In summary, the pH-dependent drug release and lysosomal accumulation of silk nanoparticles demonstrate the ability of drug-loaded silk nanoparticles to serve as a lysosomotropic anticancer nanomedicine.

Nanomedicines are emerging as promising tools to improve health. Silk nanoparticles of defined surface charge and size can be obtained using acetone desolvation and are readily loaded with a chemotherapeutic agent and used as a nanomedicine. These silk-based nanoparticles are able to serve as a lysosomotropic delivery platform and can overcome cancer cell drug resistance.

Gene therapy of diseases like cystic fibrosis (CF) would consist of delivering a gene medicine towards the lungs via the respiratory tract into the target epithelial cells. Accordingly, poly-functional nano-carriers are required in order to overcome the various successive barriers of such a complex environment, such as airway colonization with bacterial strains. In this work, the antibacterial effectiveness of a series of cationic lipids is investigated before evaluating its compatibility with gene transfer into human bronchial epithelial cells. Among the various compounds considered, some bearing a trimethyl-arsonium headgroup demonstrate very potent biocide effects towards clinically relevant bacterial strains. In contrast to cationic lipids exhibiting no or insufficient antibacterial potency, arsonium-containing lipophosphoramides can simultaneously inhibit bacteria while delivering DNA into eukaryotic cells, as efficiently and safely as in absence of bacteria. Moreover, such vectors can demonstrate antibacterial activity in vitro while retaining high gene transfection efficiency to the nasal epithelium as well as to the lungs in mice in vivo. Arsonium-containing amphiphiles are the first synthetic compounds shown to achieve efficient gene delivery in the presence of bacteria, a property particularly suitable for gene therapy strategies under infected conditions such as within the airways of CF patients.

In contrast to compounds exhibiting no (Z⁺ = N⁺) or insufficient (Z⁺ = P⁺) antibacterial effectiveness, arsonium (Z⁺ = As⁺)-containing lipophosphoramides can simultaneously inhibit bacteria while safely and efficiently delivering DNA into eukaryotic cells, thereby leading to luciferase (Luc) reporter gene expression. Such poly-functional nano-carriers may therefore be particularly suitable for gene therapy strategies under infected conditions such as within the airways of cystic fibrosis patients.

None of the clinical trials of anti-HIV gels based on conventional polymers or lipid emulsions has been successful, suggesting the need of new molecular design of the anti-HIV gels. This paper reports the conversion of anti-HIV prodrugs into self-delivery supramolecular hydrogels. By covalently conjugating reverse transcriptase inhibitors to a versatile self-assembly motif, the hydrogelators that self-assemble to form supramolecular nanofibers as the matrices of hydrogels in a weak acidic condition are obtained. Upon the treatment of prostate acid phosphatase (PAP), the hydrogels exhibit drastically enhanced elasticity. The hydrogelators are biocompatible and able to release the inhibitors under physiological condition. The use of the self-assembly motif as a self-delivery agent containing non-steroid anti-inflammatory drug (NSAID) renders this hydrogel to be both anti-inflammatory and anti-HIV. This work illustrates an unprecedented approach for designing multifunctional supramolecular hydrogels that may serve as potential anti-HIV hydrogels for sustained drug release.

The conjugation of reverse transcriptase inhibitors to a versatile self-assembly motif affords hydrogelators that self-assemble to form supramolecular nanofibers as the matrices of hydrogel. Prostate acid phosphatase drastically enhances the elasticity of hydrogels that are biocompatible and release the inhibitors. This type of hydrogels is both anti-inflammatory and anti-HIV.

Poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) is one of the most potent synthetic nonviral gene-delivery vectors because of its high transfection efficiency. However, the cytotoxicity of PDMAEMA is a major concern for its clinical applications. An anionic crosslinker is synthesized based on a natural polysaccharide, chondroitin sulfate (CS), by introducing methacrylate groups (CSMA). By systematically adjusting the substitution degree of methacrylation on CS and the weight percent of CSMA and PDMAEMA, sol-type copolymers are obtained as a gene-delivery vector. The combination of CS and PDMAEMA is expected not only to reduce the cytotoxicity of PDMAEMA, but also to facilitate better transfection efficiency than PDMAEMA because of the recognition of CS by CD44 receptors on cell surfaces. Two CSMA-modified PDMAEMA copolymers with different CSMA constituents are selected and their polyplexes prepared with plasmid DNA. The cytotoxicity and gene transfection efficiency of the polyplexes are tested and compared with those of PDMAEMA/pDNA. The copolymers of CSMA and PDMAEMA show significantly improved cell viability as compared with PDMAEMA. Their formed polyplexes with pDNA also show lower cytotoxicity than does PDMAEMA/pDNA. The transfection efficiency remarkably increases as the CSMA-modified PDMAEMA/pDNA polyplex is prepared at a weight ratio of 2.4. The internalization mechanism of CSMA-modified PDMAEMA/pDNA in HEK 293T cells is mainly based on caveolae-mediated endocytosis. However, both caveolae-mediated and CD44-mediated endocytosis mechanisms are involved in U87 cells.

An anionic crosslinker is synthesized based on a natural polysaccharide, chondroitin sulfate (CS), by introducing methacrylate groups (CSMA). By systematic adjustment of the substitution degree of methacrylation on CS and the weight percent of CSMA and poly(2-dimethylaminoethyl methacrylate) (PDMAEMA), sol-type copolymers are obtained as a gene-delivery vector. The combination of CS and PDMAEMA not only reduces the cytotoxicity of PDMAEMA, but also facilitates better transfection efficiency than PDMAEMA because of the recognition of CS by CD44 receptors on cell surfaces.

A docetaxel (DX) lipid conjugate 2′-(2-bromohexadecanoyl)-docetaxel (2-Br-C16-DX) is synthesized to enhance the drug loading, entrapment and retention in liquid oil-filled lipid nanoparticles (NPs). The conjugate is successfully entrapped in the previously optimized NPs with an entrapment efficiency of 56.8%. In-vitro release studies in 100% mouse plasma show an initial 45% burst release with no additional release within 8 hr. The conjugate is able to be hydrolyzed to release DX by esterases in-vitro. The conjugate is less potent than unmodified DX in DU-145 and 4T1 cells. However, NPs containing the conjugate show significantly higher cytotoxicity compared to its free form especially in 4T1 cells. In-vivo, the AUC_0-∞ value of NP-formulated 2-Br-C16-DX is about 100-fold higher than DX formulated in Taxotere. Furthermore, 2-Br-C16-DX NPs improve DX AUC 4.3-fold compared to Taxotere. The high concentration and prolonged exposure of both 2-Br-C16-DX and DX from 2-Br-C16-DX NPs in circulation result in a 10-fold and 1.5-fold higher accumulation of 2-Br-C16-DX and DX, respectively, in tumors compared to Taxotere. In mice bearing syngeneic 4T1 tumors, 2-Br-C16-DX NPs show markedly greater anticancer efficacy as well as survival benefit over all controls. The results of these studies support that the oil-filled NPs containing hydrolyzable lipophilic DX prodrug 2-Br-C16-DX improve the therapeutic index of DX and are more efficacious in the treatment of breast cancer.

Oil-filled lipid nanoparticles (NPs) have excellent compatibility with medium-chain ester derivatives of docetaxel (DX). The synthesized DX lipid conjugate enhances the drug loading, entrapment and retention in liquid oil-filled lipid NPs. The stable anchoring of DX lipid conjugate in the long-circulating NPs leads to significant enhancements in blood exposure and efficacy in vivo.

Magnetic spheroid manipulation can be carried out in hanging drops to generate distinctly structured heterotypic microtissues through sequential addition of cells or spheroid to homotypic spheroids. These spheroids can also be incorporated in a droplet-based assay to screen for therapeutic efficacy in prolonged studies. This simple and versatile technique can offer potential benefits in tissue engineering and drug screening applications.

Multifunctional polymersomes loaded with maghemite nanoparticles and grafted with an antibody, directed against human endothelial receptor 2, are developed as novel MRI contrast agents for bone metastasis imaging. Upon administration in mice bearing bone tumor grown from human breast cancer cells, MR images show targeting and enhanced retention of antibody-labeled polymersomes at the tumor site.

Patterning of bioactive enzymes with subcellular resolution is achieved by dispensing droplets of dextran (DEX) onto polyethylene glycol (PEG)-covered cells though a glass capillary needle connected to a pneumatic pump. This technique is applied to purify colonies of induced pluripotent stem cells (iPSCs) from mouse embryonic fibroblast (MEF) feeder cultures and inefficiently induced iPSC colonies by selectively dissociating the iPSCs with proteases.

Neural stem cells maintain their tumor tropism after internalizing gold nanorods. When exposed to a laser, the loaded cells heat up, destroying surrounding tumor cells.

Application of high-intensity focused ultrasound to drug-loaded superhydrophobic meshes affords triggered drug release by displacing an entrapped air layer. The air layer within the superhydrophobic meshes is characterized using direct visualization and B-mode imaging. Drug-loaded superhydrophobic meshes are cytotoxic in an in vitro assay after ultrasound treatment.

The combined effect of mussel-inspired polydopamine (PDA) surface functionalization and topographical cues on the behavior of skeletal myoblasts is described. On PDA-modified nanofibers, myogenic protein expression and the fusion of myoblasts are increased significantly compared with those on unmodified nanofibers. The multinucleate myotubes on the aligned nanofibers are oriented in a direction parallel to the nanofibers.

Surface functionalization of human red blood cells (hRBCs) with fluorescent and magnetic silica core-shell nanoparticles is used to design a carrier suitable for multimodal imaging with a long circulating time. The coated magnetic hRBCs show no hemolytic activity, while the advantage of the affinity of proteins for silica allows a further coating.

Our aim was to study the suitability of the ex-vivo human trabecular bone bioreactor ZetOS to test the biocompatibility of calcium phosphate bone cement composites modified with spray dried, drug loaded microspheres. We hypothesized, that this bone bioreactor could be a promising alternative to in vivo assessment of biocompatibility in living human bone over a defined time period. Composites consisting of tetracycline loaded poly(lactic-co-glycolic acid) microspheres and calcium phosphate bone cement, were inserted into in vitro cultured human femora head trabecular bone and incubated over 30 days at 37°C in the incubation system. Different biocompatibility parameters, such as lactate dehydrogenase activity, alkaline phosphatase release and the expression of relevant cytokines, IL-1β, IL-6, and TNF-α, were measured in the incubation medium. No significant differences in alkaline phosphatase, osteocalcin, and lactate dehydrogenase activity were measured compared to control samples. Tetracycline was released from the microspheres, delivered and incorporated into newly formed bone. In this study we demonstrated that ex vivo biocompatibility testing using human trabecular bone in a bioreactor is a potential alternative to animal experiments since bone metabolism is still maintained in a physiological environment ex vivo.

The evaluation of biocompatibility is an important step in the development of novel biomaterials. In the case of bone cements, such biocompatibility studies are either based on cell culture experiments or on in vivo experiments. This article presents evaluation of biocompatibility of a composite composed of bone cement and microparticulate drug delivery system in an ex vivo trabecular bone model. The presented ex vivo model is a potential alternative to animal testing with improved relevance compared to cell culture testing.

Nanoparticles target tumor cells by pH-controlled means: Nanoparticles carry three synergistic delivery functions: 1) tumor tissue targeting by the EPR effect; 2) tumor cell targeting by pHLIP-mediated membrane-localization; and 3) tumor cell uptake by adsorptive-mediated endocytosis.

Miniaturized microneedle devices are being developed for painlessly targeting vaccines to the immune cell populations in skin. As skin immunization studies are generally restricted to animal models however, where skin architecture and immunity is greatly different to human, surprisingly little is known about the local human response to intradermal (ID) vaccines. Here we use surgically excised human skin to explore for the first time the complex molecular and cellular host responses to a candidate influenza vaccine comprising nanoparticulate virus-like-particles (VLPs), administered via conventional hypodermic injection or reduced scale microneedles. Responses at the molecular level are determined by microarray analysis (47,296 discrete transcripts) and validated by quantitative PCR (96 genes). Cellular response is probed through monitoring migration of dendritic cells in viable skin tissue. Gene expression mapping, ontological analysis and qPCR reveal up-regulation of a host of genes responsible for key immunomodulatory processes and host viral response, including cell recruitment, activation, migration and T cell interaction following both ID and microneedle injection of VLPs; the response from the microneedles being more subtle. Significant morphological and migratory changes to skin dendritic cells are also apparent following microneedle VLP delivery. This is the first study displaying the global, multifaceted immunological events that occur at the site of vaccine deposition in human skin and will subsequently influence the degree and nature of innate and adaptive immune responses. An increased understanding of the detailed similarities and differences in response against antigen administered via different delivery modalities will inform the development of improved vaccines and vaccine delivery systems.

Excised human skin responds to influenza virus-like particle (VLP) vaccines delivered via intradermal (ID) or coated microneedle (MN) injection. Microarray heat maps highlight changes in expression of genes responsible for key immunomodulatory processes and viral response, including cell recruitment, activation, migration and T cell interaction. Morphological changes in Langerhans cells at the site of antigen deposition permit cell migration through the skin epidermis.

Smart biomaterials that are self-assembled from peptide amphiphiles (PA) are known to undergo morphological transitions in response to specific physiological stimuli. The design of such customizable hydrogels is of significant interest due to their potential applications in tissue engineering, biomedical imaging, and drug delivery. Using a novel coarse-grained peptide/polymer model, which has been validated by comparison of equilibrium conformations from atomistic simulations, we have performed large-scale molecular dynamics simulations to examine the spontaneous self-assembly process. Starting from initial random configurations, these simulations result in the formation of nanostructures of various sizes and shapes as a function of the electrostatics and temperature. At optimal conditions, the self-assembly mechanism for the formation of cylindrical nanofibers is deciphered involving a series of steps: (1) PA molecules quickly undergo micellization whose driving force is the hydrophobic interactions between alkyl tails; (2) neighboring peptide residues within a micelle engage in a slow ordering process that leads to the formation of β-sheets exposing the hydrophobic core; (3) spherical micelles merge together through an end-to-end mechanism to form cylindrical nanofibers that exhibit high structural fidelity to the proposed structure based on experimental data. As the temperature and electrostatics vary, PA molecules undergo alternative kinetic mechanisms, resulting in the formation of a wide spectrum of nanostructures. A phase diagram in the electrostatics-temperature plane is constructed delineating regions of morphological transitions in response to external stimuli.

Using a novel coarse-grained peptide/polymer model, large-scale molecular dynamics simulations are performed to examine spontaneous self-assembly of peptide amphiphiles resulting in the formation of nanostructures of various sizes and shapes as a function of the electrostatics and temperature. Different self-assembly mechanisms are deciphered and a phase diagram delineating regions of morphological transitions at different solvent conditions is constructed.

Bacterial cellulose (BC)-based biomaterials on medical device platforms have gained significant interest for tissue-engineered scaffolds or engraftment materials in regenerative medicine. In particular, BC has an ultrafine and highly pure nanofibril network structure and can be used as an efficient wound-healing platform since cell migration into a wound site is strongly meditated by the structural properties of the extracellular matrix. Here, we report the fabrication of a nanofibrillar patch by using BC and its application as a new wound-healing platform for traumatic tympanic membrane (TM) perforation. TM perforation is a very common clinical problem worldwide and presents as conductive hearing loss and chronic perforations. The BC nanofibrillar patch can be synthesized from Gluconacetobacter xylinus; it was found that the patch contained a network of nanofibrils and was transparent. The thickness of the BC nanofibrillar patch was found to be approximately 10.33 ± 0.58 μm, and the tensile strength and Young's modulus of the BC nanofibrillar patch were 11.85 ± 2.43 and 11.90 ± 0.48 MPa, respectively, satisfying the requirements of an ideal wound-healing platform for TM regeneration. In vitro studies involving TM cells showed that TM cell proliferation and migration were stimulated under the guidance of the BC nanofibrillar patch. In vivo animal studies demonstrated that the BC nanofibrillar patch promotes the rate of TM healing as well as aids in the recovery of TM function. Our data demonstrate that the BC nanofibrillar patch is a useful wound-healing platform for TM perforation.

A bacterial cellulose (BC) nanofibrillar patch is proposed as a new wound healing platform for tympanic membrane (TM) perforation. In vitro and in vivo studies demonstrate that the BC nanofibrillar patch promotes the TM healing speed and rate as well as recover the function of TM.

Doxorubicin, together with the modified polysaccharide (alginate dialdehyde), was used as a wall material to fabricate microcapsules through self-cross-linking by a template method. The microcapsules as-prepared are pH-responsive. Relevant scanning electronic microscopy, atom force microscopy and confocal laser scanning microscopy confirm the morphology of the uniform microcapsules. The spectroscopic results show that the microcapsules are assembled through electrostatic interaction and Schiff's base covalent bonding. Doxorubicin can be released sustainably from the capsules in buffer solution at a lower pH value. The cellular uptake of the microcapsules and drug release induced by acidic microenvironment are time-dependent processes. The cell cytotoxicity experiments in vitro demonstrate that the doxorubicin-based microcapsules have high efficiency to kill the cancer cells.

Doxorubicin is used together with the modified polysaccharide as a wall material to fabricate microcapsules through electrostatic interaction and Schiff's base covalent bonding by a simple template method. Doxorubicin can be released responsively and sustainably from the capsules in the tumor microenvironment in vitro. The cell cytotoxicity experiments demonstrate that the doxorubicin-based microcapsules have high efficiency to kill cancer cells.

Novel injectable chitosan sponges based on rapid ionic crosslinking using guanosine 5′-diphosphate are introduced. The rapid gelation, high water retention, desirable physicochemical properties, soft tissue-like mechanical properties and excellent cytocompatibility make these injectable sponges promising candidates for tissue regeneration and drug delivery applications.

Poly(amidoamine) (PAMAM) dendrimers are branched water-soluble polymers defined by consecutive generation numbers (Gn) indicating a parallel increase in size, molecular weight, and number of surface groups available for conjugation of bioactive agents. In this article, we compare the biodistribution of N-acetylgalactosamine (NAcGal)-targeted [¹⁴C]₁-G5-(NH₂)₅-(Ac)₁₀₈-(NAcGal)₁₄ particles to non-targeted [¹⁴C]₁-G5-(NH₂)₁₂₇ and PEGylated [¹⁴C]₁-G5-(NH₂)₄₄-(Ac)₇₃-(PEG)₁₀ particles in a mouse hepatic cancer model. Results show that both NAcGal-targeted and non-targeted particles are rapidly cleared from the systemic circulation with high distribution to the liver. However, NAcGal-targeted particles exhibited 2.5-fold higher accumulation in tumor tissue compared to non-targeted ones. In comparison, PEGylated particles showed a 16-fold increase in plasma residence time and a 5-fold reduction in liver accumulation. These results motivated us to engineer new PEGylated G5 particles with PEG chains anchored to the G5 surface via acid-labile cis-aconityl linkages where the free PEG tips are functionalized with NAcGal or SP94 peptide to investigate their potential as targeting ligands for hepatic cancer cells as a function of sugar conformation (α versus β), ligand concentration (100-4000 nM), and incubation time (2 and 24 hours) compared to fluorescently (Fl)-labeled and non-targeted G5-(Fl)₆-(NH₂)₁₂₂ and G5-(Fl)₆-(Ac)₁₀₇-(cPEG)₁₅ particles. Results show G5-(Fl)₆-(Ac)₁₀₇-(cPEG[NAcGal_β])₁₄ particles achieve faster uptake and higher intracellular concentrations in HepG2 cancer cells compared to other G5 particles while escaping the non-specific adsorption of serum protein and phagocytosis by Kupffer cells, which make these particles the ideal carrier for selective drug delivery into hepatic cancer cells.

Design of targeted PEGylated G5 dendrimers loaded with a chemotherapeutic agent: PEG is coupled to G5 and functionalized with NAcGal sugar molecules or SP94 peptide targeting ligands. NAcGal- and SP94-functionalized PEGylated G5 particles bind to their specific receptors expressed on the surface of hepatic cancer cells triggering receptor-mediated endocytosis, followed by PEG shedding and release of the loaded chemotherapeutic agent.

A microreplication method is presented to transfer nature optimized vascular network of leaf venation into various synthetic matrixes. The biomaterial hydrogel with these microfluidic networks is proven to facilitate the growth of endothelial cells and simultaneously function as convection pathways to transport nutrients and oxygen in a pump-free bioreactor setup, which is crucial for the long-term viability of encapsulated cells.

A novel superhydrophobic biodegradable coating with micro-/nanometer rough structure, fabricated by co-electrospraying poly(L-lactide) (PLLA) and modified silica nanoparticles (MSNs), exhibits good anti-adhesion behavior towards bacteria and cells in the initial culturing phase, which makes it a promising technology for preparing medical device coatings.

This study is focused on the crucial issue of biodegradability of graphene under in vivo conditions. We have used characteristic Raman signatures of graphene to three dimensionally (3D) image its localization in lung, liver, kidney and spleen of mouse and identified gradual development of structural disorder, happening over a period of 3 months, as indicated by the formation of defect-related D’ band, line broadening of D and G bands, increase in I_D/I_G ratio and overall intensity reduction. Prior to injection, the carboxyl functionalized graphene of lateral size ∼200 nm is well dispersed in aqueous medium, but 24 hours post injection, larger aggregates of size up to 10 μm is detected in various organs. Using Raman cluster imaging method, temporal development of disorder is detected from day 8 onwards, which began from the edges and grew inwards over a period of 3 months. The biodegradation is found prominent in graphene phagocytosed by tissue-bound macrophages and the gene expression studies of pro-inflammatory cytokines indicated the possibility of phagocytic immune response. In addition, in vitro studies conducted on macrophage cell lines also showed development of structural disorder in the engulfed graphene, reiterating the role of macrophages in biodegradation. This is the first report providing clear evidence of in vivo biodegradation of graphene and these results may radically change the perspective on potential biomedical applications of graphene.

Biodegradability of graphene is a crucial issue concerning the clinical translation of graphene based nano-bio systems. Our confocal Raman imaging study reveals clear evidence of macrophage mediated degradation of tissue bound graphene under in vivo conditions over a period of 90 days in mouse models. In vitro studies conducted in macrophage cell lines also supports the in vivo observations.

Europium-doped GdPO₄ hollow spheres/polymer core-shell nanoparticles were functionalized with ovalbumin (OVA) as a model antigen and an oligonucleotide (CpG) that stimulated the immune response. These functionalized core-shell nanoparticles were used as vaccines, where they enabled efficient delivery of an antigen to target sites, tracking of the vaccines using non-invasive clinical imaging technology.

Airway stents are often used to maintain patency of the tracheal and bronchial passages in patients suffering from central airway obstruction caused by malignant tumors, scarring, and injury. Like most conventional medical implants, they are designed to perform their functions for a limited period of time, after which surgical removal is often required. Two primary types of airway stents are in general use, metal mesh devices and elastomeric tubes; both are constructed using permanent materials, and must be removed when no longer needed, leading to potential complications. This paper describes the development of process technologies for bioresorbable prototype elastomeric airway stents that would dissolve completely after a predetermined period of time or by an enzymatic triggering mechanism. These airway stents are constructed from biodegradable elastomers with high mechanical strength, flexibility and optical transparency. This work combines microfabrication technology with bioresorbable polymers, with the ultimate goal of a fully biodegradable airway stent ultimately capable of improving patient safety and treatment outcomes.

A bioresorbable airway stent that would eliminate the current requirement for surgical removal after use is reported. This new stent, made of bioresorbable APS elastomer, is designed with mechanical properties comparable to current silicone stents, made of a novel bioresorbable elastomer, APS, which has a highly tunable stiffness, degradation rate, and a triggered degradation mechanism. Initial results of the fabrication, degradation properties, and mechanical properties of these prototype stents are reported.

Chirality plays a fundamental role not only in biological systems, but also in synthetic materials intended for bio-applications. Self-assembled monolayers (SAMs) have been prepared on gold surfaces through a “grafting to” method from racemic or enantiopure chiral poly(glycerol methacrylate)s (PGMA(rac), PGMA(R), and PGMA(S)), having a thiol endgroup. Such SAMs constitute a chemically and structurally well-defined model substrate for studying protein adsorption and cell adhesion as a function of the polymer chirality. Surface plasmon resonance measurements reveal that PGMA SAMs greatly reduce the adsorption of bovine serum albumin (BSA) compared to bare gold surfaces. Interestingly, enantiopure SAMs based on PGMA(R) or PGMA(S) show a significantly larger reduction in BSA adsorption than PGMA(rac)-covered surfaces. Studies with the monocytic cell line THP-1 show a similar relationship between enantiopurity of PGMA SAMs and the extent of cell adhesion. Ellipsometry and Raman spectroscopy measurements indicate that SAMs formed by PGMA(rac) have a higher grafting density compared to SAMs of PGMA(R) and PGMA(S). This seems to be due to the ability of PGMA(rac) to form more intermolecular hydrogen bonds among polymer chains compared to the enantiopure PGMAs. Circular dichroism spectroscopy provided evidence that enantiopure polymers adopt a chiral ordered conformation, most likely helical, in aqueous solutions. It is concluded that a higher water content of SAMs formed by enantiopure PGMA(S) and PGMA(R) SAMs arises from the macromolecular chiral conformation adopted by their enantiopure PGMA chains, and it is the decisive reason for the reduced BSA adsorption and cell adhesion as compared to PGMA(rac) SAMs.

Grafting of enantiopure chiral poly(glycerol methacrylate) onto gold effectively blocks adhesion of THP-1 cells. In contrast, broad cell spreading is observed on a bare surface, and a weak cell adhesion on a racemic self-assembled monolayer. The dissimilar cell repulsion of enantiopure and racemic coatings is due to a higher hydration of the former, an indirect result of chiral ordered conformations adopted by these enantiopure polymers.

Despite the fact that pathogenic infections are widely treated by antibiotics in the clinic nowadays, the increasing risk of multidrug-resistance associated with abuse of antibiotics is becoming a major concern in global public health. The increased death toll caused by pathogenic bacterial infection calls for effective antibiotic alternatives. Lysozyme-coated mesoporous silica nanoparticles (MSNs⊂Lys) are reported as antibacterial agents that exhibit efficient antibacterial activity both in vitro and in vivo with low cytotoxicity and negligible hemolytic side effect. The Lys corona provides multivalent interaction between MSNs⊂Lys and bacterial walls and consequently raises the local concentration of Lys on the surface of cell walls, which promotes hydrolysis of peptidoglycans and increases membrane-perturbation abilities. The minimal inhibition concentration (MIC) of MSNs⊂Lys is fivefold lower than that of free Lys in vitro. The antibacterial efficacy of MSNs⊂Lys is evaluated in vivo by using an intestine-infected mouse model. Experimental results indicate that the number of bacteria surviving in the colon is three orders of magnitude lower than in the untreated group. These natural antibacterial enzyme-modified nanoparticles open up a new avenue for design and synthesis of next-generation antibacterial agents as alternatives to antibiotics.

Efficient antibacterial agents in vitro and in vivo: Lys-coated mesoporous silica nanoparticles (MSNs⊂Lys) with bacterial targetability and adhesive capabilities show five-fold enhanced antibacterial activity in vitro and over two-fold antibacterial efficacy in the intestines of mice, as compared to controls.

Nano-GO is a graphene derivative with a 2D atomic layer of sp² bonded carbon atoms in hexagonal conformation together with sp³ domains with carbon atoms linked to oxygen functional groups. The supremacy of nano-GO resides essentially in its own intrinsic chemical and physical structure, which confers an extraordinary chemical versatility, high aspect ratio and unusual physical properties. The chemical versatility of nano-GO arises from the oxygen functional groups on the carbon structure that make possible its relatively easy functionalization, under mild conditions, with organic molecules or biological structures in covalent or non-covalent linkage. The synergistic effects resulting from the assembly of well-defined structures at nano-GO surface, in addition to its intrinsic optical, mechanical and electronic properties, allow the development of new multifunctional hybrid materials with a high potential in multimodal cancer therapy. Herein, a comprehensive review of the fundamental properties of nano-GO requirements for cancer therapy and the first developments of nano-GO as a platform for this purpose is presented.

The synergistic effects resulting from the assembly of well-defined structures at the nano-GO surface, in addition to its morphology, surface chemistry and its intrinsic optical, mechanical and electronic properties, allow the development of new multifunctional hybrid materials with a high potential in multimodal cancer therapy. A comprehensive review of the fundamental properties of nano-GO requirements for cancer therapy and the first developments of nano-GO as a platform for this purpose is presented.

Extremely efficacious gene transfection vector: The rapid and facile modification of PEI with commercially available TMC produces an extremely efficacious gene delivery vector with minimal cytotoxicity. Functionalization of PEI is easily controlled by PEI:cyclic carbonate feed ratios and allows for the addition of functionality. Modified PEIs hold great potential as gene delivery systems due to easy synthesis, scalability, low cost, low toxicity and outstanding transfection capacity

The majority of anticancer therapeutics have failed to control the target cancers. Thus, new rational design concepts are critical. In most of the biological reactions, a cascade pathway is used to activate appropriate responses. In the cascade pathway, a small signal derived from neighboring environments can be amplified and it further triggers overwhelming and specialized responses. It can be applied to achieve powerful therapeutic effects for novel drug design strategies. Inspired by this concept, we design a preferential dual anti-cancer therapeutic cassette composed of (i) DNA/RNA nanostructures as both anticancer containers and target ligands and (ii) a gold nanocrystal as localized heat inducers. We demonstrate that this multi-modular platform is superior to conventional cancer medications in that it had higher drug loading efficiency, tunable drug release, and intrinsic serum stability characteristics. Both doxorubicin chemotherapy and thermal ablation exert a powerful synergistic killing effect that resulted in prostate cancer regression both in vitro and in vivo. We speculate that our novel anti-cancer drug system can be adapted to effectively destroy many different types of solid cancers.

A dual therapeutic cassette is presented composed of two distinct compartments that contain the combined nanostructures of (1) DNA and RNA as both anticancer container and target ligand and (2) gold nanocrystal as a localized heat inducer. This multimodular platform shows a powerful synergistic killing effect that results in prostate cancer regression both in vitro and in vivo.

Current cancer therapies are challenged by weakly soluble drugs and by drug combinations that exhibit non-uniform biodistribution and poor bioavailability. In this study, we have presented a new platform of advanced healthcare materials based on albumin nanoparticles (ANPs) engineered as tumor penetrating, delivery vehicles of combinatorially applied factors to solid tumors. These materials were designed to overcome three sequential key barriers: tissue level transport across solid tumor matrix; uptake kinetics into individual cancer cells; therapeutic resistance to single chemotherapeutic drugs. The ANPs were designed to penetrate deeper into solid tumor matrices using collagenase decoration and evaluated using a three-dimensional multicellular melanoma tumor spheroid model. Collagenase modified ANPs exhibited 1-2 orders of magnitude greater tumor penetration than unmodified ANPs into the spheroid mass after 96 hours, and showed preferential uptake into individual cancer cells for smaller sized ANPs (<100 nm). For enhanced efficacy, collagenase coated ANPs were modified with two therapeutic agents, curcumin and riluzole, with complementary mechanisms of action for combined cell cycle arrest and apoptosis in melanoma. The collagenase coated, drug loaded nanoparticles induced significantly more cell death within 3-D tumor models than the unmodified, dual drug loaded ANP particles and the kinetics of cytotoxicity was further influenced by the ANP size. Thus, multifunctional nanoparticles can be imbued with complementary size and protease activity features that allow them to penetrate solid tumors and deliver combinatorial therapeutic payload with enhanced cancer cytotoxicity but minimal collateral damage to healthy primary cells.

Recombinant human albumin derived nanoparticles (ANPs) are engineered to overcome multiple barriers that challenge drug delivery and tumor chemotherapy. By integrating distinct technological features of nanoscale size variation, collagenase decoration, and modification with dual, complementary drugs (curcumin and riluzole), the ANPs can undergo enhanced intracellular uptake, penetrate deeper into solid tumor matrices, and exhibit significantly enhanced overall efficacy against melanoma in a tumor spheroid model.

A disulfide-crosslinked hydrogel made from ultrasmall peptides is introduced. Crosslinked gels are more elastic and better able to maintain shape integrity. Using facile chemistry, RGD (or other bioactive signals) can be conjugated onto the peptide fibers. Gels formed are biocompatible and support the three-dimensional distribution of cells.

Propionibacterium acnes (P. acnes) is a Gram-positive bacterium strongly associated with acne infection. While many antimicrobial agents have been used in clinic to treat acne infection by targeting P. acnes, these existing anti-acne agents usually produce considerable side effects. Herein, we report the development and evaluation of liposomal lauric acids (LipoLA) as a new, effective and safe therapeutic agent for the treatment of acne infection. By incorporating lauric acids into the lipid bilayer of liposomes, we observed that the resulting LipoLA readily fused with bacterial membranes, causing effective killing of P. acnes by disrupting bacterial membrane structures. Using a mouse ear model, we demonstrated that the bactericidal property of LipoLA against P. acne was well preserved at physiological conditions. Topically applying LipoLA in a gel form onto the infectious sites led to eradication of P. acnes bacteria in vivo. Further skin toxicity studies showed that LipoLA did not induce acute toxicity to normal mouse skin, while benzoyl peroxide and salicylic acid, the two most popular over-the-counter acne medications, generated moderate to severe skin irritation within 24 h. These results suggest that LipoLA hold a high therapeutic potential for the treatment of acne infection and other P. acnes related diseases.

This article reports the development and in vivo evaluation of liposomal lauric acids (LipoLA) as a new, effective and safe nanotherapeutic agent for the treatment of Propionibacterium acnes infection. Using a mouse ear model, topically applying LipoLA in a gel form onto the infectious site results in completely killing the bacteria without inducing acute toxicity to normal skin.

Elaborating a bone replacement using tissue-engineering strategies for bone repair seems to be a promising remedy. However, previous platforms are limited in constructing three-dimensional porous scaffolds and neglected the critical importance of periosteum (a pivotal source of osteogenic cells for bone regeneration). We report here an innovative method using the periosteum as a template to replicate its exquisite morphologies onto the surfaces of biomaterials. The precise topographic cues (grooved micropatterns) on the surface of collagen membrane inherited from the periosteum effectively directed cell alignment as the way of natural periosteum. Besides, we placed the stem-cell and endothelial-cell-laden collagen membrane (pseudo-periosteum) onto a three-dimensional porous scaffold. The pseudo-periosteum-covered scaffolds showed remarkable osteogenesis when compared with the pseudo-periosteum-free scaffolds, indicating the significant importance of pseudo-periosteum on bone regeneration. This study gives a novel concept for the construction of bone tissue engineering scaffold and may provide new insight for periosteum research.

A newly developed collagen based pseudo-periosteum that simulates the motif of native perisoteum has a strong influence on spatially alignment and proliferation of stem cells. Importantly, the pseudo-periosteum-covered porous scaffold significantly promotes osteogenesis when compared with the pseudo-periosteum-free scaffold, indicating the important potential of periosteum in bone remolding and healing.

Herein, a new class of multifunctional materials combining a clustered nanoparticle-based probe is presented for surface enhanced Raman scattering (SERS)-based microscopy and surface functionalization for tissue targeting. Controlled assembly of spherical gold nanoparticles into dimers (DNP-REP) is engineered using a small, rigid Raman-active dithiolated linking reporter (REP) to yield narrow internanoparticle gaps and to strategically generate the “hot spot” while concurrently placing the reporter within the region of highest SERS enhancement. Peptide functionalized DNP-REP materials are highly stable even upon incubation with living cells and show controlled levels of binding and intracellular endocytosis. To demonstrate the functionality of such probes for disease detection, differentially targeted DNP-REPs are incubated over various time points with cultured human glioblastoma cells. Using human glioblastoma cells, the SERS maps of targeted tumor cells show the markedly enhanced signals of the DNP-REP, compared to conventional confocal fluorescence based approaches, especially at low incubation times. Even with as few as 40 internalized DNP-REP, a relatively intense SERS signal is measured, demonstrating the high signal to noise ratio and inherent biocompatibility of the materials. Thus, these Raman reporter-based nanoparticle cluster probes present a promising and versatile optical imaging tool for fast, reliable, selective, and ultrasensitive tissue targeting and disease detection and screening.

Dimers of gold nanoparticles are employed to build surface enhanced Raman scattering (SERS)-based tags. The nanoparticles are held together by a small Raman-active molecular linker and surface-functionalized with stabilizing polyethylene glycol, fluorescent dyes, and cell-specific targeting moieties. Upon incubation with cancerous cells, the tags demonstrate high sensitivity at low incubation times, high selectivity, retained activity upon endocytosis, low cytotoxicity, and more effective tumor phenotype detection compared to traditional fluorescence- based approaches.

Sensitive, rapid and phenotype-specific enumeration of pathogens is essential for the diagnosis of infectious disease, monitoring of food chains, and for defense against bioterrorism. Microbiological culture and genotyping, techniques that sensitively and selectively detect bacteria in laboratory settings, have limited application in clinical environments due to high cost, slow response times, and the need for specially trained staff and laboratory infrastructure. To address these challenges, we developed a microfluidic chip-based micro-Hall (μHall) platform capable of measuring single, magnetically tagged bacteria directly in clinical specimens with minimal sample processing. We demonstrated the clinical utility of the μHall chip by enumerating Gram-positive bacteria. The overall detection limit of the system was similar to that of culture tests (∼10 bacteria), but the assay time was 50-times faster. This low-cost, single-cell analytical technique is especially well-suited to diagnose infectious diseases in resource-limited clinical settings.

A microHall (μHall) sensor platform is developed to detect rare pathogens in unprocessed clinical samples. The system employes an array of μHall elements to accurately enumerate individual, magnetically tagged bacteria under flow conditions. It allows direct bacterial detection in unprocessed samples, which not only improves the overall throughput but also simplifies assay procedures.

Individualized disease treatment is a promising branch for future medicine. In this work, we introduce an implantable microelectromechanical system (MEMS) based drug delivery device for programmable drug delivery. An in vitro study on cancer cell treatment has been conducted to demonstrate a proof-of-concept that the engineered device is suitable for individualized disease treatment. This is the first study to demonstrate that MEMS drug delivery devices can influence the outcome of cancer drug treatment through the use of individualized disease treatment regimes, where the strategy for drug dosages is tailored according to different individuals. The presented device is electrochemically actuated through a diaphragm membrane and made of polydimethylsiloxane (PDMS) for biocompatibility using simple and cost-effective microfabrication techniques. Individualized disease treatment was investigated using the in vitro programmed delivery of a chemotherapy drug, doxorubicin, to pancreatic cancer cell cultures. Cultured cell colonies of two pancreatic cancer cell lines (Panc-1 and MiaPaCa-2) were treated with three programmed schedules and monitored for 7 days. The result shows that the colony growth has been successfully inhibited for both cell lines among all the three treatment schedules. Also, the different observations between the two cell lines under different schedules reveal that MiaPaCa-2 cells are more sensitive to the drug applied. These results demonstrate that further development on the device will provide a promising novel platform for individualized disease treatment in future medicine as well as for automatic in vitro assays in drug development industry.

A MEMS device is designed and fabricated for programmable drug delivery. The device is demonstrated to be used for tailoring the drug dosages for disease treatment in an in vitro study on pancreatic cancer cell colonies. It provides a promising novel platform for individualized disease treatment in future medicine and automatic in vitro test in drug development industry.

The potential for the use of well-defined nanopatterns to control stem cell behaviour on surfaces has been well documented on polymeric substrates. In terms of translation to orthopaedic applications, there is a need to develop nanopatterning techniques for clinically relevant surfaces, such as the load-bearing material titanium (Ti). In this work, a novel nanopatterning method for Ti surfaces is demonstrated, using anodisation in combination with PS-b-P4VP block copolymer templates. The block copolymer templates allows for fabrication of titania nanodot patterns with precisely controlled dimensions and positioning which means that this technique can be used as a lithography-like patterning method of bulk Ti surfaces on both flat 2D and complex shaped 3D surfaces. In vitro studies demonstrate that precise tuning of the height of titania nanodot patterns can modulate the osteogenic differentiation of mesenchymal stem cells. Cells on both the 8 nm and 15 nm patterned surfaces showed a trend towards a greater number of the large, super-mature osteogenic focal adhesions than on the control polished Ti surface, but the osteogenic effect was more pronounced on the 15 nm substrate. Cells on this surface had the longest adhesions of all and produced larger osteocalcin deposits. The results suggest that nanopatterning of Ti using the technique of anodisation through a block copolymer template could provide a novel way to enhance osteoinductivity on Ti surfaces.

A novel technique combining the precision of block copolymer templating with anodisation allows for highly defined nanopatterning of non-planar Ti surfaces. Highly ordered titania nanodots can be created, and the technique has the capability for fine tuning of topography dimensions. In vitro results show that these nanopatterns have the potential to improve osteoinduction at Ti implant surfaces.

Graphene oxide can be loaded on cotton fabrics via various ways, and such a composite shows high anti-bacterial properties with minimal skin irritation.

A small molecule, glucosamine, is used as targeting moiety for insulin-secreting beta cell separation in artificial cell mixtures and tissue samples. The specificity of glucosamine allows it to be used in cell sorting applications. In addition, a thrombin-specific cleavable peptide was used as an intermediary to release nanoparticles from cell surfaces to facilitate cell attachment and proliferation.

Self-assembling, concentrated, lipid-based oxygen microparticles (LOMs) have been developed to administer oxygen gas when injected intravenously, preventing organ injury and death from systemic hypoxemia in animal models. Distinct from blood substitutes, LOMs are a one-way oxygen carrier designed to rescue patients who experience life-threatening hypoxemia, as caused by airway obstruction or severe lung injury. Here, we describe methods to manufacture large quantities of LOMs using an in-line, recycling, high-shear homogenizer, which can create up to 4 liters of microparticle emulsion in 10 minutes, with particles containing a median diameter of 0.93 microns and 60 volume% of gas phase. Using this process, we screen 30 combinations of commonly used excipients for their ability to form stable LOMs. LOMs composed of DSPC and cholesterol in a 1:1 molar ratio are stable for a 100 day observation period, and the number of particles exceeding 10 microns in diameter does not increase over time. When mixed with blood in vitro, LOMs fully oxygenate blood within 3.95 seconds of contact, and do not cause hemolysis or complement activation. LOMs can be manufactured in bulk by high shear homogenization, and appear to have a stability and size profile which merit further testing.

Lipid-based oxygen microparticles have been described as a means to administer oxygen gas intravenously as a means to reverse systemic hypoxemia. This work describes the bulk manufacture of concentrated, gas-filled microparticles using a high shear homogenizer, creating microparticles which are stable at room temperature for 100 days. These microparticles transfer oxygen to human blood within seconds of contact in vitro, without signs of hemolysis or complement activation.

Lactococcus lactis is modified to express a fibronectin fragment (FNIII_7-10) as a membrane protein. This interphase, based on a living system, can be further exploited to provide spatio-temporal factors to direct cell function at the material interface. This approach establishes a new paradigm in biomaterial surface functionalization for biomedical applications.

We report the use of multifunctional dendrimer-modified multi-walled carbon nanotubes (MWCNTs) for targeted and pH-responsive delivery of doxorubicin (DOX) into cancer cells. In this study, amine-terminated generation 5 poly(amidoamine) (PAMAM) dendrimers modified with fluorescein isothiocyanate (FI) and folic acid (FA) were covalently linked to acid-treated MWCNTs, followed by acetylation of the remaining dendrimer terminal amines to neutralize the positive surface potential. The formed multifunctional MWCNTs (MWCNT/G5.NHAc-FI-FA) were characterized via different techniques. Then, the MWCNT/G5.NHAc-FI-FA was used to load DOX for targeted and pH-responsive delivery to cancer cells overexpressing high-affinity folic acid receptors (FAR). We showed that the MWCNT/G5.NHAc-FI-FA enabled a high drug payload and encapsulation efficiency both up to 97.8% and the formed DOX/MWCNT/G5.NHAc-FI-FA complexes displayed a pH-responsive release property with fast DOX release under acidic environment and slow release at physiological pH conditions. Importantly, the DOX/MWCNT/G5.NHAc-FI-FA complexes displayed effective therapeutic efficacy, similar to that of free DOX, and were able to target to cancer cells overexpressing high-affinity FAR and effectively inhibit the growth of the cancer cells. The synthesized multifunctional dendrimer-modified MWCNTs may be used as a targeted and pH-responsive delivery system for targeting therapy of different types of cancer cells.

An effective targeted and pH-responsive drug delivery system: The unique combination of dendrimer chemistry and carbon nanotubes allows the generation of multifunctional nanodevices for high-payload encapsulation of a model anticancer drug doxorubicin with pH-responsive release behavior and targeting specificity, providing an efficient strategy for targeted cancer therapy.

Platelet-rich-plasma (PRP) has attracted great attention and has been increasingly used for a variety of clinical applications including orthopedic surgeries, periodontal and oral surgeries, maxillofacial surgeries, plastic surgeries, and sports medicine. However, very little is known about the antimicrobial activities of PRP. PRP is found to have antimicrobial properties both in vitro and in vivo. In vitro, the antimicrobial properties of PRP are bacterial-strain-specific and time-specific: PRP significantly (80-100 fold reduction in colony-forming units) inhibits the growth of methicillin-sensitive and methicillin-resistant Staphylococcus aureus, Group A streptococcus, and Neisseria gonorrhoeae within the first few hours but it has no significant antimicrobial properties against E. coli and Pseudomonas. The antimicrobial properties of PRP also depend on the concentration of thrombin. In vivo, an implant-associated spinal infection rabbit model is established and used to evaluate the antimicrobial and wound-healing properties of PRP. Compared to the infection controls, PRP treatment results in significant reduction in bacterial colonies in bone samples at all time points studied (i.e. 1, 2, and 3 weeks) and significant increase in mineralized tissues (thereby better bone healing) at postoperative weeks 2 and 3. PRP therefore may be a useful adjunct strategy against postoperative implant-associated infections.

Platelet-rich-plasma (PRP) shows unique antimicrobial properties both in vitro and in vivo. An implant-associated spinal infection rabbit model shows that PRP treatment leads to a significant reduction in bacterial burdens together with a significant improvement in wound healing. PRP could be an advanced healthcare material against postoperative implant-associated infections.

A dense diamond nanoneedle array is capable of rapidly and conveniently delivering fluorescent probe and drug molecules to a large number of cells. This simple approach paves the way for potential high-throughput delivery of genes, drugs, and fluorescent probes into cells without endocytosis.

Elastin-like polypeptides (ELPs) are polypentapeptides that undergo hydrophobic collapse and aggregation above a specific transition temperature, T_t. ELP diblocks sharing a common “core” block (I60) but varying “outer” blocks (A80, P40) were designed, where T_t,I < T_t,A < T_t,P. The formation of ∼55 nm diameter mixed micelles from these ELP diblocks was verified using dynamic light scattering (DLS), multiangle light scattering (MALS) and fluorescence resonance energy transfer (FRET). To confer affinity to the blood circulating protein fibrinogen, a fibrinogen-binding tetrapeptide sequence (GPRP) was fused to A80-I60, while P40-I60 was fused to a non-binding control (GPSP). The self-assembling, peptide-displaying, mixed micelles exhibit temperature-modulated avidities for immobilized and soluble fibrinogen at 32 °C and 42 °C. In this initial proof-of-concept design, the engineered mixed micelles were shown to disengage fibrinogen at elevated temperatures. The modular nature of this system can be used for developing in vivo depot systems that will only be triggered to release in situ upon specific stimuli.

Protein-based mixed micelles with variable avidities to fibrinogen at different temperature regimes are reported. Such a system has potential drug delivery applications as a blood circulating depot that will only be released in situ upon a specific trigger such as temperature (in the current design), pH or oxidative stress.

This work illustrates a strategy for the design of molecularly defined immunotherapies, using a blend of supramolecular peptide self-assembly and active site-directed protein capture.

Scaffolds have been reported to promote healing of hard-to-heal wounds such as burns and chronic ulcers. However, there has been little investigation into the cell biology of wound edge tissues in response to the scaffolds. Here, we assess the impact of collagen scaffolds on mouse full-thickness wound re-epithelialisation during the first 5 days of healing. We find that scaffolds impede wound re-epithelialisation, inducing a bulbous thickening of the wound edge epidermis as opposed to the thin tongue of migratory keratinocytes seen in normal wound healing. Scaffolds also increase the inflammatory response and the numbers of neutrophils in and around the wound. These effects were also produced by scaffolds made of alginate in the form of fibers and microspheres, but not as an alginate hydrogel. In addition, we find the gap junction protein connexin 43, which normally down-regulates at the wound edge during re-epithelialisation, to be up-regulated in the bulbous epidermal wound edge. Incorporation of connexin 43 antisense oligodeoxynucleotides into the scaffold can be performed to reduce inflammation whilst promoting scaffold biocompatibility.

The in vivo wound healing response to polymer scaffolds at the cell biology level remains little investigated. Here, a variety of scaffolds are applied to wounds and it was found that re-epithelialisation was perturbed and the gap junction protein Connexin 43 is deleteriously up-regulated. Through bioactivation of scaffolds using Connexin 43 antisense oligodeoxynucleotides, the biocompatibility of scaffolds for clinical use can be improved.

SS-cleavable proton-activated lipid-like material (ssPalm) functions as a key element in a lipid nanoparticle in which pDNA is encapsulated. The ssPalm contains dual sensing motifs that can respond to the intracellular environment; a proton-sponge unit (tertiary amines) that functions in response to an acidic environment (endosome/lysosome), and disulfide bonding that can be cleaved in a reducing environment (cytosol).

Free-standing, micropatterned silica nanotube membranes are in situ fabricated using a micropatterned silica-coated collagen hybrid hydrogel as template. They are substrate-free, and not only maintained their micropatterned microstructure well, but also exhibited strong cell contact guidance ability to direct cell alignment and differentiation, indicating their good potential for biomedical applications.

We describe the self-folding of photopatterned poly (ethylene glycol) (PEG)-based hydrogel bilayers into curved and anatomically relevant micrometer-scale geometries. The PEG bilayers consist of two different molecular weights (MWs) and are photocrosslinked en masse using conventional photolithography. Self-folding is driven by differential swelling of the two PEG bilayers in aqueous solutions. We characterize the self-folding of PEG bilayers of varying composition and develop a finite element model which predicts radii of curvature that are in good agreement with empirical results. Since we envision the utility of bio-origami in tissue engineering, we photoencapsulate insulin secreting β-TC-6 cells within PEG bilayers and subsequently self-fold them into cylindrical hydrogels of different radii. Calcein AM staining and ELISA measurements are used to monitor cell proliferation and insulin production respectively, and the results indicate cell viability and robust insulin production for over eight weeks in culture.

Hydrogel bilayers containing photoencapsulated cells self-fold into curved and micropatterned bio-origami geometries. Self-folding is driven by differential swelling of the hydrogel layers and a variety of microstructured bilayers can be photopatterned simultaneously. Bio-origami hydrogels can be used to direct the growth of cells into anatomically relevant 3D geometries for long-term cell culture studies.

New switchable hydrogels are developed. Under acidic conditions, hydrogels undergo self- cyclization and can catch and kill bacteria. Under neutral/basic conditions, hydrogels undergo ring-opening and can release killed bacterial cells and resist protein adsorption and bacterial attachment. Smart hydrogels also show a dramatically improved mechanical property which is highly desired for biomedical applications.

Three-dimensional cellular models that mimic disease are being increasingly investigated and have opened an exciting new research area into understanding pathomechanisms. The advantage of 3D in vitro disease models is that they allow systematic and in-depth studies of physiological and pathophysiological processes with less costs and ethical concerns that have arisen with animal models. The purpose of the 3D approach is to allow crosstalk between cells and microenvironment, and with cues from the microenvironment, cells can assemble their niche similar to in vivo conditions. The use of 3D models for mimicking disease processes such as cancer, osteoarthritis etc., is only emerging and allows multidisciplinary teams consisting of tissue engineers, biologist biomaterial scientists and clinicians to work closely together. While in vitro systems require rigorous testing before they can be considered as replicates of the in vivo model, major steps have been made, suggesting that they will become powerful tools for studying physiological and pathophysiological processes. This paper aims to summarize some of the existing 3D models and proposes a novel 3D model of the eye structures that are involved in the most common cause of blindness in the Western World, namely age-related macular degeneration (AMD).

Current three dimensional culture models mimicking organ systems and disease concepts in vitro are reviewed. It is predicted that these models will become increasingly important for understanding pathomechanisms of disease, drug screening and testing. Advancements in combining engineered micro-environments with human cell lines that mimic retinal architecture may also allow the study of disease mechanisms such as those occurring in age-related macular degeneration, the most common cause of blindness in the Western World.

Recently, significant progress has been made in developing “stimuli-sensitive” biomaterials as a new therapeutic approach to interact with dynamic physiological conditions. Reactive oxygen species (ROS) production has been implicated in important pathophysiological events, such as atherosclerosis, aging, and cancer. ROS are often overproduced locally in diseased cells and tissues, and they individually and synchronously contribute to many of the abnormalities associated with local pathogenesis. Therefore, the advantages of developing ROS-responsive materials extend beyond site-specific targeting of therapeutic delivery, and potentially include navigating, sensing, and repairing the cellular damages via programmed changes in material properties. Here we review the mechanism and development of biomaterials with ROS-induced solubility switch or degradation, as well as their performance and potential for future biomedical applications.

The recent development of reactive oxygen specie (ROS)-responsive materials is inspired from numerous disease states, such as cancer and inflammation, involving the overproduction of ROS. ROS-responsive materials available today employ two general mechanisms: i) solubility switch and ii) degradation upon exposure to ROS. These materials can be used for drug and cell delivery to interact with the pathophysiological states more intelligently.

Cell migration is dependent on a number of physical and chemical parameters of the substrate that influence cellular signaling events as cell surface receptors interact with the substrate. These events can strengthen or loosen the contact of the cell with its environment and need to be orchestrated for efficient motility. A set of tunable substrates was used in combination with quantitative imaging to probe for potentially subtle differences in genetically modified and chemically treated rapidly migrating cells. As model cell, Plasmodium sporozoites were used, the forms of malaria parasites transmitted by the mosquito to the host. Sporozoites lacking a substrate-binding surface protein moved on different surfaces with consistently lower efficiency and were more sensitive to adhesion ligand spacing than wild type sporozoites. Addition of an actin filament stabilizing chemical agent temporarily increased sporozoite motility on soft but not on hard substrates. Defined conditions were found where the chemical completely compensates the reduced migration capacity of the genetically modified parasites. As the onset of motility was delayed for sporozoites on unfavourable gels it is suggested that the parasite can slowly adjust to environmental elasticity, possibly by adapting the interplay between surface adhesins and actin filament dynamics. This demonstrates the utility of tunable substrates to dissect molecular function in cell adhesion and motility.

Malaria parasites can move extremely fast on different substrates. Using a set of tunable substrates with changed ligand spacing and elasticity it is shown that a small chemical compound that stabilizes the actin cytoskeleton can compensate the motility defects of parasites that lack a surface protein important for substrate adhesion.

A method to functionalize steerable magnetic microdevices through the co-electrodeposition of drug loaded chitosan hydrogels is presented. The characteristics of the polymer matrix have been investigated in terms of fabrication, morphology, drug release and response to different environmental conditions. Modifications of the matrix behavior could be achieved by simple chemical post processing. The system is able to load and deliver 40–80 μg cm⁻² of a model drug (Brilliant Green) in a sustained manner with different profiles. Chitosan allows a pH responsive behavior with faster and more efficient release under slightly acidic conditions as can be present in tumor or inflamed tissue. A prototype of a microrobot functionalized with the hydrogel is presented and proposed for the treatment of posterior eye diseases.

Chitosan drug loaded matrices are electrodeposited on conductive surfaces and modified by simple dip coating processes with an ionic crosslinker solution. Drug release is evaluated in different pH conditions mimicking possible changes due to local inflammation or disease. The method is intended to functionalize capsules for drug delivery into the eye.

We report an approach to preventing bacterial biofilm formation that is based on the surface-mediated release of 5,6-dimethyl-2-aminobenzimidazole (DMABI), a potent and non-bactericidal small-molecule inhibitor of bacterial biofilm growth. Our results demonstrate that DMABI can be encapsulated in thin films of a model biocompatible polymer [poly(lactide-co-glycolide), PLG] and be released in quantities that inhibit the formation of Pseudomonas aeruginosa biofilms by up to 75–90% on surfaces that otherwise support robust biofilm growth. This approach enables the release of this new anti-biofilm agent for over one month, and it can be used to inhibit biofilm growth on both film-coated surfaces and other adjacent surfaces (e.g., on other uncoated surfaces and at air/water interfaces). Our results demonstrate a non-bactericidal approach to the prevention of biofilm growth and provide proof of concept using a clinically relevant human pathogen. In contrast to coatings designed to kill bacteria on contact, this approach should also permit the design of strategically placed depots that disseminate DMABI more broadly and exert inhibitory effects over larger areas. In a broader context, the non-bactericidal nature of DMABI could also provide opportunities to address concerns related to evolved resistance that currently face approaches based on the release of traditional microbicidal agents (e.g., antibiotics). Finally, the results of initial in vitro mammalian cell culture studies indicate that DMABI is not toxic to cells at concentrations required for strong anti-biofilm activity, suggesting that this new agent is well suited for further investigation in biomedical and personal care contexts.

Bacterial biofilms pose persistent and costly challenges in many healthcare contexts. A non-bactericidal approach to preventing biofilm formation in the human pathogen P. aeruginosa is reported. The approach is based on the gradual release of a potent, non-bactericidal inhibitor of biofilm growth from thin polymer coatings, and can inhibit biofilm formation on film-coated surfaces and adjacent uncoated interfaces by up to 90%. This small-molecule inhibitor is not toxic to mammalian cells at concentrations required for strong anti-biofilm activity, suggesting that this approach is suited for further investigation in biomedical contexts.

An accurate measurement of the immune status in patients with immune system disorders is critical in evaluating the stage of diseases and tailoring drug treatments. The functional cellular immunity test is a promising method to establish the diagnosis of immune dysfunctions. The conventional functional cellular immunity test involves measurements of the capacity of peripheral blood mononuclear cells to produce pro-inflammatory cytokines when stimulated ex vivo. However, this “bulk” assay measures the overall reactivity of a population of lymphocytes and monocytes, making it difficult to pinpoint the phenotype or real identity of the reactive immune cells involved. In this research, we develop a large surface micromachined poly-dimethylsiloxane (PDMS) microfiltration membrane (PMM) with high porosity, which is integrated in a microfluidic microfiltration platform. Using the PMM with functionalized microbeads conjugated with antibodies against specific cell surface proteins, we demonstrated rapid, efficient and high-throughput on-chip isolation, enrichment, and stimulation of subpopulations of immune cells from blood specimens. Furthermore, the PMM-integrated microfiltration platform, coupled with a no-wash homogeneous chemiluminescence assay (“AlphaLISA”), enables us to demonstrate rapid and sensitive on-chip immunophenotyping assays for subpopulations of immune cells isolated directly from minute quantities of blood samples.

An integrated microfluidic microfiltration platform containing a unique surface micromachined poly-dimethylsiloxane (PDMS) microfiltration membrane (PMM) and microbeads conjugated with antibodies is reported for rapid, efficient and high-throughput on-chip isolation, enrichment, and stimulation of subpopulations of immune cells from blood specimens. Furthermore, the PMM-integrated microfiltration platform, coupled with a no-wash homogeneous chemiluminescence assay (“AlphaLISA”), allows rapid and sensitive on-chip immunophenotyping assays for subpopulations of immune cells isolated directly from minute quantities of blood samples.

Dendritic cells (DCs) are an important target for vaccine delivery. It is shown that antibody functionalized polymer capsules can effectively target DCs; however, the internalization is highly dependent on the specific receptor targeted. This work highlights the importance of considering factors such as how the antibody/capsule is internalized, rather than just the target specificity.

Therapeutic polylactide (PLA) nanofibrous matrices are fabricated by incorporating plant viral nanoparticles (PVNs) infused with fluorescent agents ethidium bromide (EtBr) and rhodamine (Rho), and cancer therapeutic doxorubicin (Dox). The native virus, Red clover necrotic mosaic virus (RCNMV), reversibly opens and closes upon exposure to the appropriate environmental stimuli. Infusing RCNMV with small molecules allows the incorporation of PVN^Active into fibrous matrices via two methods: direct processing by in situ electrospinning of a polymer and PVNs solution or immersion of the matrix into a viral nanoparticle solution. Five organic solvents commonly in-use for electrospinning are evaluated for potential negative impact on RCNMV stability. In addition, leakage of rhodamine from the corresponding PVN^Rho upon solvent exposure is determined. Incorporation of the PVN into the matrices are evaluated via transmission electron, scanning electron and fluorescent microscopies. Finally, the percent cumulative release of doxorubicin from both PLA nanofibers and PLA and polyethylene oxide (PEO) hybrid nanofibers demonstrate tailored release due to the incorporation of PVN^Dox as compared to the control nanofibers with free Dox. Preliminary kinetic analysis results suggest a two-phase release profile with the first phase following a hindered Fickian transport mechanism for the release of Dox for the polymer-embedded PVNs. In contrast, the nanofiber matrices that incorporate PVNs through the immersion processing method followed a pseudo-first order kinetic transport mechanism.

Therapeutic poly(lactic acid) (PLA) nanofibrous matrices can trigger drug release through hybrid fabrication with plant viral nanoparticles (PVNs). PVNs comprise the native virus, Red clover necrotic mosaic virus, and a cancer therapeutic, doxorubicin. PVNs reversibly open and close with the appropriate environmental stimuli; the drug releases from the virus and diffuses through the polymeric matrix.

Oral mucositis, a painful and debilitating ulcerative wound condition, is a frequently occurring complication following chemo- and/or radiotherapy. While the current standards of therapy (e.g., gels and mouth rinses) provide temporary relief, there is still an unmet need for a robust, long acting barrier that can provide lubricating protection in oral wounds, thereby enhancing the wound healing response. It is proposed that an affinity based layer-by-layer (LBL) self-assembly that can be administered as a series of mouth rinses could permit the formation of protective barriers, providing a modular approach to regenerative oral therapy. In this study, biotinylated poly(acrylic acid) was synthesized for developing LBL assemblies using biotin-streptavidin affinity linkages. To explore the ability of developed LBL assemblies to potentially resist the harsh intraoral environment, in vitro chemical and ex vivo mechanical tests were performed. The stability results demonstrated significant LBL barrier stability with wear resistance. From statistical analyses, it was deduced that polymer MW and the number of LBL layers contributed significantly to chemical barrier stability. Also, the extent of biotin conjugation played a key role for LBL development and in mechanical barrier stability. Thus, the proposed affinity based LBLs with their excellent barrier properties offer a modular treatment approach in oral mucosal injuries.

In order to overcome the inadequacies in current oral mucosal treatment methods, a modular treatment strategy is proposed which utilize biotin-streptavidin affinity linkages for developing multilayered polymeric self-assemblies. It is hypothesized that affinity based layer-by-layers (LBL) can be self-assembled through a series of mouth rinse over the oral wound surface, which will offer a desired regenerative treatment strategy through its stable barrier effects. Hence, evaluating the barrier stability of LBLs against harsh intraoral environment is a key requirement to validate its application in oral wounds.

Exposure to carbon nanotubes induces significant changes in cellular biomechanics. Using nanoindentation, it is observed that the exposed cells have significantly higher stiffness when compared to controls, especially at the nuclear region, and significant increases in surface area.

Reducing ferromagnetic particle size is an important strategy to improve their positive effect on image through the suppression of their negative effect, demonstrated by ultrasmall manganese ferrite nanoparticles prepared from an environmentally-friendly aqueous route. These ultrasmall particles exhibit pronounced paramagnetic characteristics and nontoxicity, making them efficient T₁-positive contrast agent and manganese contrast agents for manganese enhanced MRI.

Because toxic heavy metals tend to bioaccumulate, they represent a substantial human health hazard. Various methods are used to identify and quantify toxic metals in biological tissues and environment fluids, but a simple, rapid, and inexpensive system has yet to be developed. To reduce the necessity for instrument-dependent analysis, we developed a single, pH-dependent, nanosphere (NS) sensor for naked-eye detection and removal of toxic metal ions from drinking water and physiological systems (i.e., blood). The design platform for the optical NS sensor is composed of double mesoporous core–shell silica NSs fabricated by one-pot, template-guided synthesis with anionic surfactant. The dense shell-by-shell NS construction generated a unique hierarchical NS sensor with a hollow cage interior to enable accessibility for continuous monitoring of several different toxic metal ions and efficient multi-ion sensing and removal capabilities with respect to reversibility, longevity, selectivity, and signal stability. Here, we examined the application of the NS sensor for the removal of toxic metals (e.g., lead ions from a physiological system, such as human blood). The findings show that this sensor design has potential for the rapid screening of blood lead levels so that the effects of lead toxicity can be avoided.

An optical nanosphere sensor is developed for the removal of toxic metals from drinking water and blood. The sensor design creates highly accessible, flexible, and fine-tuned surfaces, which make unique sensing/removal systems that are inexpensive, simple, and highly sensitive to multiple metal ions. The design exhibits potential counteractions and inhibitions toward toxic effects associated with elevated blood lead levels.

The excellent cytocompatibility of single-layer CVD graphene is demonstrated by showing that primary adult retinal ganglion cells can directly survive on its surface without any supporting glial layer or protein coating. These results confirm the great potential of graphene as a biocompatible material for interfacing neurons, opening a new route for the development of a novel generation of flexible and high-sensitive neural prostheses.

Shear-thinning hydrogels are useful in numerous applications, including as injectable carriers that act as scaffolds to support cell and drug therapies. Here, we describe the engineering of a self-assembling Dock-and-Lock (DnL) system that forms injectable shear-thinning hydrogels using molecular recognition interactions that also possess photo-triggerable secondary crosslinks. These DnL hydrogels are fabricated from peptide-modified hyaluronic acid (HA) and polypeptide precursors, can self-heal immediately after shear induced flow, are cytocompatible, and can be stabilized through light-initiated radical polymerization of methacrylate functional groups to tune gel mechanics and erosion kinetics. Secondary crosslinked hydrogels retain self-adhesive properties and exhibit cooperative physical and chemical crosslinks with moduli as high as ∼10 times larger than moduli of gels based on physical crosslinking alone. The extent of reaction and change in properties are dependent on whether the methacrylate is incorporated either at the terminus of the peptide or directly to the HA backbone. Additionally, the gel erosion can be monitored through an incorporated fluorophore and physical–chemical gels remain intact in solution over months, whereas physical gels that are not covalently crosslinked erode completely within days. Mesenchymal stem cells exhibit increased viability when cultured in physical– chemical gels, compared with those cultured in gels based on physical crosslinks alone. The physical properties of these DnL gels may be additionally tuned by adjusting component compositions, which allows DnL gels with a wide range of physical properties to be constructed for use.

A two-component hydrogel based on a Dock-and-Lock self-assembling mechanism is engineered with photo-triggerable secondary crosslinks. Physical Dock-and-Lock hydrogels are based on specific molecular interactions between polypeptide components and are injectable and rapidly self-healing. Secondary crosslinked physical- chemical hydrogels have increased mechanical properties, slower erosion, and remain self-adhesive.

A straightforward and versatile method for immobilizing macromolecules and silver nanoparticles on the surface of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) electrospun fibers is developed with the objective of designing a new functional material having significant antibacterial activity. The approach relies on a two-step procedure: UV photografting of poly(methacrylic acid) (PMAA) on the surface of PHBHV fibers according to a “grafting from” method, and complexation of in situ photogenerated silver nanoparticles (Ag NPs) by carboxyl groups from tethered PMAA chains. The photografting process is conducted through a photoinduced free-radical process employing a ketone-based photoinitiator in aqueous medium. Under appropriate conditions, the photogenerated radicals abstract hydrogen atoms from the PHBHV backbone, thus initiating the UV-mediated photopolymerization of MAA from the PHBHV microfibrous surface. The photochemical mechanism of the ketone photolysis is entirely described by the electron spin resonance/spin-trapping technique, and the modified PHBHV microfibrous scaffold is extensively characterized by ATR-FTIR spectroscopy, water contact-angle measurements, and mercury intrusion porosimetry. In a second step, the in situ synthesis of Ag NPs within the microfibrous scaffold is implemented by photoreduction reaction in the presence of both a silver precursor and a photosensitizer. The photoinduced formation of Ag NPs is confirmed by UV spectrophotometry and XPS analysis. SEM and TEM experiments confirm the formation and dispersion of Ag NPs on the surface of the modified fibers. Finally, a primary investigation is conducted to support the antibacterial activity of the new functionalized biomaterial against Staphylococcus aureus and Escherichia coli.

Silver-containing PHBHV-g-PMAA microfibrous scaffolds with antibacterial activity are successfully engineered according to a sustainable “green chemistry” approach. It relies on a two-step procedure: UV photografting of poly(methacrylic acid) (PMAA) in aqueous media from the surface of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) fibers via a “grafting from” method, followed by the complexation of the in situ photogenerated silver nanoparticles immobilized by carboxyl groups from tethered PMAA chains.

The promise of a new nanomaterial, Cu_2–xSe nanocrystals, as a contrast agent for photoacoustic imaging is demonstrated. The Cu_2–xSe nanocrystals exhibit strong optical absorption at near infrared wavelengths that can efficiently penetrate tissue. In vivo photoacoustic tomography using this nanomaterial as the contrast agent provides clear three-dimensional resolution of a sentinel lymph node in a rat model.

The synthesis of mesoporous silica/calcium phosphate composite loaded with the immunopotentiator tuberculin purified protein derivative (PPD-MS/CaP) as an effective adjuvant for cancer immunotherapy is reported here. The PPD-MS/CaP adjuvant is prepared by immersing mesoporous silica in a supersaturated calcium phosphate solution supplemented with the immunopotentiator PPD for 24 h. PPD is coprecipitated with calcium phosphate inside and on the surface of mesoporous silica. By loading the immunopotentiator PPD in the PPD-MS/CaP adjuvant, an enhanced activation of antigen-presenting cells, such as GM-CSF secretion by THP-1 differentiated macrophages, is obtained probably due to sustained PPD release and an efficient cellular uptake of PPD. The PPD-MS/CaP adjuvant mixed with liquid-N₂-treated tumor tissue effectively triggers anti-tumor immune response and markedly inhibits in vivo tumor growth. The PPD-MS/CaP adjuvant is a promising alternative for cancer immune therapy.

Mesoporous silica/calcium phosphate composite loaded with immunopotentiator tuberculin purified protein derivative (PPD-MS/CaP) as an effective adjuvant for cancer immunotherapy is synthesized. The adjuvant induces an enhanced activation of antigen-presenting cells, such as GM-CSF secretion by differentiated THP-1 cells. The adjuvant mixed with liquid-N₂-treated tumor tissue effectively triggers anti-tumor immune response and greatly inhibits in vivo tumor growth.

Natural protein based nano-/microparticles are manufactured and functionalized by BMP-2. The functionalized particles can associate with mesenchymal stem cells actively, boost differentiation, alleviate cytotoxicity and perform controlled release.

The mesoporous structure of sol-gel prepared gadolinium and europium doped silicate nanoparticles has been found to be highly dependent on the formulated composition, with synthesised samples displaying both disordered and hexagonally ordered mesoporous packing symmetry. The degree of pore ordering within the nanoparticles has a strong correlation with the total lanthanide (Gd³⁺ and Eu³⁺) concentration. The gadolinosilicates are excellent magnetic resonance imaging (MRI) longitudinal (T₁) agents. The longitudinal relaxivity (r₁) and transverse (r₂) relaxivity, a measure of MRI contrast agent efficiency, were up to four times higher than the clinically employed Omniscan (gadodiamide); with r₁ up to 20.6 s⁻¹ mM⁻¹ and r₂ of 66.2 s⁻¹ mM⁻¹ compared to 5.53 and 4.64 s⁻¹ mM⁻¹, respectively, for Omniscan. In addition, the europium content of all the samples studied is below the self-quenching limit, which results in a strong luminescence response from the nanoparticles on excitation at 250 nm. The Eu-Gd silicate nanoparticles act as bimodal imaging agents for MRI and luminescence. These mesoporous nanoparticles also have the potential to serve as encapsulation and controlled release matrices for pharmaceuticals. They are therefore a promising multimodal theranostic platform.

Gadolinium and europium ions are incorporated into a mesoporous silicate framework; a potential theranostic platform to achieve bimodal medical imaging capability. These nanomaterials outperform the commercially available T₁ MRI contrast agent, Omniscan with the added benefit of exhibiting photoluminescence properties.

Upon controlled UV illumination, disulfide bonds in bovine α-lactalbumin (BLA) are selectively broken, leading to self-assembly of the BLA and doxorubicin (DOX) molecules into nanoparticles via hydrophobic interactions and intermolecular disulfide bonds. Such protein–drug nanoparticles have synergistic anticancer activity in vitro and tumor-homing specificity in vivo, which are of great potential for systemic drug delivery in cancer therapy.

A novel strategy for combination chemotherapy (platinum and demethylcantharidin) via a polymer–(tandem drugs) conjugate for enhanced cancer treatment is demonstrated. Cisplatin can be released inside cell by reduction to attack DNA, while DMC will be hydrolyzed subsequently to block DNA-damage-induced defense mechanisms by serine/threonine phosphatase PP2A inhibition. Synergistic effect of the polymer–(tandem drugs) conjugate causes complete suppression of H22 liver tumor xenografts without recurrence.

Kappa carrageenan (κ-CA) is a natural-origin polymer that closely mimics the glycosaminoglycan structure, one of the most important constituents of native tissues extracellular matrix. Previously, it has been shown that κ-CA can crosslink via ionic interactions rendering strong, but brittle hydrogels. In this study, we introduce photocrosslinkable methacrylate moieties on the κ-CA backbone to create physically and chemically crosslinked hydrogels highlighting their use in the context of tissue engineering. By varying the degree of methacrylation, the effect on hydrogel crosslinking was investigated in terms of hydration degree, dissolution profiles, morphological, mechanical, and rheological properties. Furthermore, the viability of fibroblast cells cultured inside the photocrosslinked hydrogels was investigated. The combination of chemical and physical crosslinking procedures enables the formation of hydrogels with highly versatile physical and chemical properties, while maintaining the viability of encapsulated cells. To our best knowledge, this is the first study reporting the synthesis of photocrosslinkable κ-CA with controllable compressive moduli, swelling ratios and pore size distributions. Moreover, by micromolding approaches, spatially controlled geometries and cell distribution patterns could be obtained, thus enabling the development of cell-material platforms that can be applied and tailored to a broad range of tissue engineering strategies.

Functionalization of kappa carrageenan by introducing photocrosslinkable moieties enables the formation of dual crosslinked hydrogels. The modification results in formation of highly porous hydrogel networks with tunable mechanical properties that can bear repetitive loading cycles without deformation. By micromolding approaches, fabrication of spatially controlled geometries renders the development of cell-patterned platforms for different biomedical and biotechnological applications.

A novel method for fabricating both multilayer stacked 2D and 3D tubular constructs composed of sheets of aligned collagen fibers is described. These structures are created by decellularizing native tendon and sectioning the material into thin sheets using a cryo-microtome. This fabrication method preserves the collagens natural strength as well as the fiber structure which would aid in directing aligned cell growth.

The native transportation protein serum albumin represents an attractive nano-sized transporter for drug delivery applications due to its beneficial safety profile. Existing albumin-based drug delivery systems are often limited by their low drug loading capacity as well as noticeable drug leakage into the blood circulation. Therefore, a unique albumin-derived core-shell doxorubicin (DOX) delivery system based on the protein denaturing-backfolding strategy was developed. 28 DOX molecules were covalently conjugated to the albumin polypeptide backbone via an acid sensitive hydrazone linker. Polycationic and pegylated human serum albumin formed two non-toxic and enzymatically degradable protection shells around the encapsulated DOX molecules. This core-shell delivery system possesses notable advantages, including a high drug loading capacity critical for low administration doses, a two-step drug release mechanism based on pH and the presence of proteases, an attractive biocompatibility and narrow size distribution inherited from the albumin backbone, as well as fast cellular uptake and masking of epitopes due to a high degree of pegylation. The IC₅₀ of these nanoscopic onion-type micelles was found in the low nanomolar range for Hela cells as well as leukemia cell lines. In vivo data indicate its attractive potential as anti-leukemia treatment suggesting its promising profile as nanomedicine drug delivery system.

A human serum albumin derived core-shell DOX delivery system is prepared based on an innovative protein denaturing-backfolding strategy. This system possesses a considerable DOX loading capacity, a two-step controlled drug release mechanism, attractive biocompatibility and narrow size distribution inherited from the monodisperse albumin backbone, as well as fast cellular uptake and masking of HSA epitopes due to cationization and pegylation.

Osteochondral tissue engineering poses the challenge of combining both cartilage and bone tissue engineering fundamentals. In this study, a sphere-templating technique was applied to fabricate an integrated bi-layered scaffold based on degradable poly(hydroxyethyl methacrylate) hydrogel. One layer of the integrated scaffold was designed with a single defined, monodispersed pore size of 38 μm and pore surfaces coated with hydroxyapatite particles to promote regrowth of subchondral bone while the second layer had 200 μm pores with surfaces decorated with hyaluronan for articular cartilage regeneration. Mechanical properties of the construct as well as cyto-compatibility of the scaffold and its degradation products were elucidated. To examine the potential of the biphasic scaffold for regeneration of osteochondral tissue the designated cartilage and bone layers of the integrated bi-layered scaffold were seeded with chondrocytes differentiated from human mesenchymal stem cells and primary human mesenchymal stem cells, respectively. Both types of cells were co-cultured within the scaffold in standard medium without soluble growth/differentiation factors over four weeks. The ability of the integrated bi-layered scaffold to support simultaneous matrix deposition and adequate cell growth of two distinct cell lineages in each layer during four weeks of co-culture in vitro in the absence of soluble growth factors was demonstrated.

A degradable integrated bi-layered scaffold for osteochondral tissue engineering is fabricated. The ability of the scaffold to support in vitro simultaneous matrix deposition, adequate cell growth and cell differentiation of two distinct cell lineages, human mesenchymal stem cells and chondrocytes, in designated bone and cartilage layers of the scaffold, is demonstrated.

This work describes a magnetic separation-based approach using polymyxin B-functionalized metal alloy nanomagnets for the rapid elimination of endotoxins from human blood in vitro and functional assays to evaluate the biological relevance of the blood purification process. Playing a central role in gram-negative sepsis, bacteria-derived endotoxins are attractive therapeutic targets. However, both direct endotoxin detection in and removal from protein-rich fluids remains challenging. We present the synthesis and functionalization of ultra-magnetic cobalt/iron alloy nanoparticles and a magnetic separation-based approach using polymyxin B-functionalized nanomagnets to remove endotoxin from human blood in vitro. Conventional chromogenic Limulus Amebocyte Lysate assays confirm decreased endotoxin activity in purified compared to untreated samples. Functional assays assessing key steps in host defense against bacteria show an attenuated inflammatory mediator expression from human primary endothelial cells in response to purified blood samples compared to untreated blood and less chemotactic activity. Exposing Escherichia coli-positive blood samples to polymyxin B-functionalized nanomagnets even impairs the ability of gram-negative bacteria to form colony forming units, thus making magnetic separation based blood purification a promising new approach for future sepsis treatment.

Playing a central role in the development of gram-negative sepsis, endotoxins are attractive therapeutic targets. However, their direct removal from protein-rich fluids remains challenging. We present a magnetic separation-based approach using polymyxin B-functionalized metal nanomagnets to eliminate endotoxin from human blood in vitro. Functional assays show an attenuated inflammatory response from human endothelial cells and less chemotactic activity in purified samples.

Assuring cell adhesion to an underlying biomaterial surface is vital in implant device design and tissue engineering, particularly under circumstances where cells are subjected to potential detachment from overriding fluid flow. Cell–substrate adhesion is a highly regulated process involving the interplay of mechanical properties, surface topographic features, electrostatic charge, and biochemical mechanisms. At the nanoscale level, the physical properties of the underlying substrate are of particular importance in cell adhesion. Conventionally, natural, pro-adhesive, and often thrombogenic, protein biomaterials are frequently utilized to facilitate adhesion. In the present study, nanofabrication techniques are utilized to enhance the biological functionality of a synthetic polymer surface, polymethymethacrylate, with respect to cell adhesion. Specifically we examine the effect on cell adhesion of combining: 1. optimized surface texturing, 2. electrostatic charge and 3. cell adhesive ligands, uniquely assembled on the substrata surface, as an ensemble of nanoparticles trapped in nanowells. Our results reveal that the ensemble strategy leads to enhanced, more than simply additive, endothelial cell adhesion under both static and flow conditions. This strategy may be of particular utility for enhancing flow-resistant endothelialization of blood-contacting surfaces of cardiovascular devices subjected to flow-mediated shear.

A novel method utilizing nanofabrication techniques is used to create surfaces with enhanced endothelial adhesion and retention under flow. The system utilizes nanotexture, charge, and ligands all combined together, uniquely assembled on the substrata surface, to create ensemble nanotextured surfaces. This system may be of particular utility for enhancing flow-resistant endothelialization of cardiovascular devices.

The “tower microneedle” (TM) via reverse drawing lithography for intravitreal injection by fabricating a long hollow microneedle on the blunt hypodermic needle: The hollow hole between the microneedle and hypodermic needle is aligned concentrically, and fifteen degree bevel angle is introduced to TM by laser cutting to achieve intravitreal injection with minimal damage to eye tissue.

Injury to articular cartilage, especially the defects induced by degenerative diseases has presented insurmountable challenges. Elaborating a replacement of articular cartilage using biomimic tissue-engineering strategies provides a promising remedy. However, none of the previous osteo/chondrogenic methodologies can not only simultaneously induce osteo/chondrogenesis of stem cells in one scaffolding niche, but also generate a biomimic interface between the formed osteogenic and chondrogenic zones. We report here an innovative method using biomicrofluidic techniques to simultaneously steer distinct specialized differentiation of stem cells into chondrocytes and osteoblasts in one hydrogel slab. Importantly, a gradient that mimics the interface of bone-to-cartilage was generated in the middle of the hydrogel slab. We compared this format with the conventional method for osteochondrogenesis; this format using the gradient-generating microfluidic device indicated outstanding superiorities in stem cell culture and differentiation. Our findings will have a major impact on the design of versatile biomicrofluidic devices for interfacial tissue regeneration.

A stem cell-encapsulated hydrogel laden microfluidic device with the function of gradient generation that can steer distinct specialized differentiation of stem cells on the hydrogel slab was developed in this study. This microfluidic model can be used to construct the interfacial tissues such as articular cartilage and relevant osteointegration of the cartilage graft.

Drug release triggered by an external non-invasive stimulus is of great interest for the development of new drug delivery systems. The preparation of an electroresponsive multiwalled carbon nanotube/poly(methylacrylic acid) (MWNT/PMAA)-based hybrid material is reported. The hydrogel hybrids achieve a controlled drug release upon the ON/OFF application of an electric field, giving rise to in vitro and in vivo pulsatile release profiles.

Plasticity and reciprocity of breast cancer cells to various extracellular matrice (ECMs) are three-dimensionally analyzed in quantitative way in a novel and powerful microfluidic in vitro platform. This successfully demonstrates the metastatic potential of cancer cells and their effective strategies of ECM proteolytic remodeling and morphological change, while interacting with other cells and invading into heterogeneous ECMs.

A successful combination of anti-biofouling and ion-interaction for endotoxin (ET) selective removal from protein solutions is realized via the immobilization of two ordinary polymers, PEG and PLL, which have protein resistance and endotoxin adsorption properties, respectively, together onto azide-functional polystyrene (PS-N₃) microspheres (MSs) using a surface click reaction. Toxic copper ions residu is successfully minimized by the addition of 2,2′-bipyridine (BiPy).

Porous scaffolds for tissue engineering applications consisting of hollow alginate fibers are presented. They are prepared using self-made shell/core nozzles and a 3D plotting device. Such materials open up the possibility to generate biodegradable tissue constructs with a preformed vascular system or can act as matrices for engineering of complex organs or 3D tissue models.

A multicomponent magneto-dendritic nanosystem (MDNS) was designed for rapid tumor cell targeting, isolation, and high-resolution imaging by a facile bioconjugation approach. The highly efficient and rapid-acting MDNS provides a convenient platform for simultaneous isolation and high-resolution imaging of tumor cells, potentially leading towards an early diagnosis of cancer.

Silicon micro- and nanofabrication are used to create innovative biomedical technologies and provide a suitable means to support rapid clinical translation. The review on page 632 by Alessandro Grattoni and co-workers covers a broad spectrum of silicon nanosystems ranging from diagnostics to therapeutics.

Biodegradable porous silicon nanoparticles (pSiNP) functionalized with cancer cell targeting antibodies and loaded with the hydrophobic anti-cancer drug camptothecin are developed by Nicolas H. Voelcker, Frédérique Cunin, and co-workers on page 718. High targeting and killing efficiency is demonstrated in vitro on three types of cancer cells: neuroblastoma, glioblastoma and lymphoma cells.

Islets encapsulation is a promising approach for the treatment of Type I diabetes. On page 667, Daniel G. Anderson and co-workers report a novel design of microcapsules with core–shell structures using two-fluid co-axial electro-jetting. Improved encapsulation and diabetes correction is achieved in a single step by simply confining the islets in the core region of the capsules.

This manuscript constitutes a review of several innovative biomedical technologies fabricated using the precision and accuracy of silicon micro- and nanofabrication. The technologies to be reviewed are subcutaneous nanochannel drug delivery implants for the continuous tunable zero-order release of therapeutics, multi-stage logic embedded vectors for the targeted systemic distribution of both therapeutic and imaging contrast agents, silicon and porous silicon nanowires for investigating cellular interactions and processes as well as for molecular and drug delivery applications, porous silicon (pSi) as inclusions into biocomposites for tissue engineering, especially as it applies to bone repair and regrowth, and porous silica chips for proteomic profiling. In the case of the biocomposites, the specifically designed pSi inclusions not only add to the structural robustness, but can also promote tissue and bone regrowth, fight infection, and reduce pain by releasing stimulating factors and other therapeutic agents stored within their porous network. The common material thread throughout all of these constructs, silicon and its associated dielectrics (silicon dioxide, silicon nitride, etc.), can be precisely and accurately machined using the same scalable micro- and nanofabrication protocols that are ubiquitous within the semiconductor industry. These techniques lend themselves to the high throughput production of exquisitely defined and monodispersed nanoscale features that should eliminate architectural randomness as a source of experimental variation thereby potentially leading to more rapid clinical translation.

The precision of silicon micro- and nanofabrication is used to create a range of innovative biomedical technologies. This review covers several of these technologies, including nanochannel implants, embedded vectors, nanowires, biocomposite porous silicon(pSi), and porous silica chips. The materials, silicon and its dielectrics, are produced using the high-throughput techniques ubiquitous within the semiconductor industry, with defined nanoscale features that could lead to rapid clinical translation.

Islets microencapsulation holds great promise to treat type 1 diabetes. Currently used alginate microcapsules often have islets protruding outside capsules, leading to inadequate immuno-protection. A novel design of microcapsules with core–shell structures using a two-fluid co-axial electro-jetting is reported. Improved encapsulation and diabetes correction is achieved in a single step by simply confining the islets in the core region of the capsules.

Modular assembly of protein–polysaccharide microenvironments into 3D macroscale tissue constructs is reported. Rapid and simple centrifugation and vacuum molding methods are used to create cohesive multiphase constructs with prescribed geometries. Human fibroblasts are shown to survive in the microenvironments and in the macroscale constructs. Control of the spatial organization in engineered tissues is a key to recreating the complex tissue architectures needed for regenerative therapies.

Bone formation and regeneration is a prolonged process that requires a slow drug release system to assist in the long-term recovery. A drug-delivery system is developed that allows for the controlled release of simvastin, without exhibiting the side effects associated with high concentrations of simvastatin, and is still capable of inducing constant bone formation.

Calcium phosphate nanoplates and nanorods with controllable pores and enhanced protein loading and tuneable release characteristics are first synthesized without the use of any toxic surfactants by an energy efficient microwave assisted chemical process, hence demonstrating their viability as a tool for controllable drug delivery in biomaterial systems.

The hierarchical electrostatic deposition of anionic microgels and a cationic oligopeptide throughout a PCL-chitosan nanofiber scaffold inhibits S. epidermidis colonization of the scaffold interior while promoting osteoblast adhesion, spreading, and proliferation on the scaffold surface.

A novel cationic liposome nanocarrier, having interesting performance in topical drug delivery, is here presented and evaluated for its features. Two penetration enhancers, namely monoolein and lauroylcholine chloride, are combined to rapidly formulate (15 min) a cationic liposome nanostructure endowed of excellent stability (>6 months) and skin penetration ability, along with low short-term cytotoxicity, as evaluated via the MTT test. Cytotoxicity tests and lipid droplet analysis give a strong indication that monoolein and lauroylcholine synergistically endanger long-term cells viability. The physicochemical features, investigated through SAXS, DLS, and cryo-TEM techniques, reveal that the nanostructure is retained after loading with diclofenac in its acid (hydrophobic) form. The drug release performances are studied using intact newborn pig skin. Analysis of the different skin strata proves that the drug mainly accumulates into the viable epidermis with almost no deposition into the derma. Indeed, the flux of the drug across the skin is exceptionally low, with only 1% release after 24 h. These results validate the use of this novel formulation for topical drug release when the delivery to the systemic circulation should be avoided.

Liposomes based on monoolein and lauroylcholine chloride are taken up by 3T3 fibroblasts. Liposome treatment induces lipid droplets formation as shown by Nile Red staining. Green fluorescent lipid droplets become intense 4 h after the treatment. Nuclear staining with Hoechst 33258 revealed nuclear morphology of viable cells.

Novel clinical grade electrospinning methods could provide three-dimensional (3D) nanostructured biomaterials comprising of synthetic or natural biopolymer nanofibers. Such advanced materials could potentially mimic the natural extracellular matrix (ECM) accurately and may provide superior niche-like spaces on the subcellular scale for optimal stem-cell attachment and individual cell homing in regenerative therapies. The goal of this study was to design several novel “nanofibrous extracellular matrices” (NF-ECMs) with a natural mesh-like 3D architecture through a unique needle-free multi-jet electrospinning method in highly controlled manner to comply with good manufacturing practices (GMP) for the production of advanced healthcare materials for regenerative medicine, and to test cellular behavior of human mesenchymal stem cells (HMSCs) on these.

Biopolymers manufactured as 3D NF-ECM meshes under clinical grade GMP-like conditions show higher intrinsic cytobiocompatibility with superior cell integration and proliferation if compared to their 2D counterparts or a clinically-approved collagen membrane.

A novel electrospinning process for engineering three-dimensional nanofi-brous extracellular matrixes (NFECMs) is initiated using a NanoSpider machine. Under clinical grade goodmanufacturing-practice-like conditions, several NF-ECMs are designed in a controlled manner to yield highly uniform fibers with sub-micrometer dimensions, favourable biomechanical properties and intrinsic cytobiocompatility. This permits both the proliferation and differentiation of human mesenchymal stem cells when provided appropriate biological cues.

We describe the preparation of biodegradable porous silicon nanoparticles (pSiNP) functionalized with cancer cell targeting antibodies and loaded with the hydrophobic anti-cancer drug camptothecin. Orientated immobilization of the antibody on the pSiNP is achieved using novel semicarbazide based bioconjugate chemistry. To demonstrate the generality of this targeting approach, the three antibodies MLR2, mAb528 and Rituximab are used, which target neuroblastoma, glioblastoma and B lymphoma cells, respectively. Successful targeting is demonstrated by means of flow cytometry and immunocytochemistry both with cell lines and primary cells. Cell viability assays after incubation with pSiNPs show selective killing of cells expressing the receptor corresponding to the antibody attached on the pSiNP.

Mesoporous silicon nanoparticles that are able to specifically target and deliver hydrophobic anti-cancer drugs to cancer cells are developed. Porous silicon nanoparticles are functionalized with antibodies in a controlled way, in order to efficiently target cancer cells expressing the corresponding receptor. High targeting and killing efficiency is demonstrated in vitro on three types on cancer cells: neuroblastoma, glioblastoma and lymphoma cells.

Multiwalled carbon nanotubes (MWCNTs) possess unique properties rendering them a potentially useful biomaterial for neurobiological applications such as providing nanoscale contact-guidance cues for directing axon growth within peripheral nerve repair scaffolds. The in vitro biocompatibility of MWCNTs with postnatal mouse spinal sensory neurons was assessed for this application. Cell culture medium conditioned with MWCNTs was not significantly toxic to dissociated cultures of postnatal mouse dorsal root ganglia (DRG) neurons. However, exposure of DRG neurons to MWCNTs dispersed in culture medium resulted in a time- and dose-dependent reduction in neuronal viability. At 250 μg mL⁻¹, dispersed MWCNTs caused significant neuronal death and unusual neurite morphologies illustrated by immunofluorescent labelling of the cytoskeletal protein beta (III) tubulin, however, at a dose of 5 μg mL⁻¹ MWCNTs were nontoxic over a 14-day period. DRG neurons grown on fabricated MWCNT substrates produced neurite outgrowths with abnormal morphologies that were significantly inferior in length to neurons grown on the control substrate laminin. This evidence demonstrates that to be utilized as a biomaterial in tissue scaffolds for nerve repair, MWCNTs will require robust surface modification to enhance biocompatibility and growth promoting properties.

Multiwalled carbon nanotubes (MWCNTs) have been reported as a potential material for application in neurobiological scaffolds. However, our results demonstrate that compared to laminin, a basement membrane protein found in axon pathways, MWCNTs provide an inferior substrate for the growth of postnatal dorsal root ganglia neurons. These findings suggest that although neurons will grow on MWCNT substrates, these substrates require surface modification to support optimal neurite outgrowth.

Prostate specific membrane antigen (PSMA) is overexpressed on prostate tumor cells and the neovascular endothelia various solid tumors. A bivalent immunotoxin generated by fusing a fold-back single-chain diabody derived from the Fv fragments of an anti-PSMA monoclonal antibody with a truncated diphtheria toxin (DT) containing the activity and translocation domains [A-dmDT390-scfbDb(PSMA)] might be suitable for targeted therapy of tumors that overexpress PSMA. In this study, a PSMA-positive and a PSMA-negative prostate cancer cell lines were treated with immunotoxin A-dmDT390-scfbDb(PSMA) in order to study the tumor targeting specificity and therapeutic potential of the immunotoxin. The cellular uptake and selective toxicity of the immunotoxin were evident in monolayer cultures of PSMA-positive LNCaP prostate cancer cells but not in cultures of PSMA-negative PC-3 prostate cancer cells. Cellular accumulation of A-dmDT390-scfbDb(PSMA) increased with increasing incubation times and concentrations in LNCaP cells. The proportion of apoptotic LNCaP cells increased upon incubation with increasing doses of the fold-back immunotoxin. Optical imaging and MRI with the Alexa Fluor 680-labeled A-dmDT390-scfbDb(PSMA) confirmed the specific targeting and therapeutic efficacy of this immunotoxin towards PSMA-positive LNCaP solid tumor xenografts in athymic nude mice.

An immunotoxin is produced which is effective for targeted killing and selective imaging of PSMA-expressing prostate cancer cells grown in vitro and in vivo. This immunotoxin is without effect on prostate cancer cells that are deficient in PSMA expression and may find theranostic use in the clinic for selectively treating tumors that overexpress PSMA.

Most synthetic polymer hydrogel tissue adhesives and sealants swell considerably in physiologic conditions, which can result in mechanical weakening and adverse medical complications. This paper describes the synthesis and characterization of mechanically tough zero- or negative-swelling mussel-inspired surgical adhesives based on catechol-modified amphiphilic poly(propylene oxide)-poly(ethylene oxide) block copolymers. The formation, swelling, bulk mechanical, and tissue adhesive properties of the resulting thermosensitive gels were characterized. Catechol oxidation at or below room temperature rapidly resulted in a chemically cross-linked network, with subsequent warming to physiological temperature inducing a thermal hydrophobic transition in the PPO domains and providing a mechanism for volumetric reduction and mechanical toughening. The described approach can be easily adapted for other thermally sensitive block copolymers and cross-linking strategies, representing a general approach that can be employed to control swelling and enhance mechanical properties of polymer hydrogels used in a medical context.

Adhesive hydrogels that negatively swell at physiological temperature are presented. By combining mussel-mimetic chemistry and the thermosensitive nature of poly(ethylene oxide)-poly(propylene oxide) copolymers, novel materials are designed that are suitable as medical sealants and adhesives.

Lymph nodes (LNs) are often removed to prevent the spread of cancer because they are frequently the first site of metastases. However, the enucleation of LNs requires difficult operative techniques and lymphedema can result as a complication. Although lymphedema can be cured by anastomosis of a lymph vessel (LV) to a vein, the operative procedure is extremely difficult because LNs and LVs are too small and indistinct to be identified. Therefore, visualization of LNs and LVs is important. The combination of X-ray computed tomography (CT) and fluorescence imaging, CT/fluorescence dual modal imaging, enables the visualization of LNs and LVs before and during surgery. To accomplish this, near-infrared fluorescent silica-coated gold nanoparticle clusters (Au@SiO₂) with a high X-ray absorption coefficient are synthesized. Both fluorescence imaging and CT show that the Au@SiO₂ nanoparticles gradually accumulate in LNs through LVs. CT determines the location and size of the LNs and LVs without dissection, and fluorescence imaging facilitates their identification. The Au@SiO₂ nanoparticles have neither hepatotoxicity nor nephrotoxicity. The results demonstrate that CT/fluorescence dual modal imaging using Au@SiO₂ nanoparticles provides anatomical information, including the location and size of LNs and LVs for determining a surgery plan, and provides intraoperative visualization of LNs and LVs to facilitate the operation.

Computed tomography/fluorescence dual modal imaging using near-infrared fluorescent silica-coated gold nanoparticle clusters provides anatomical information, including the location and size of lymph nodes (LNs) and lymphatic vessels (LVs) for designing a surgery plan. It can also provide intraoperative visualization of LNs and LVs to facilitate the operation.