Advanced Healthcare Materials

Soft rod-like polymer particles flowing through a blood vessel are presented by Frank Caruso and co-workers on page 35. The geometry and mechanics of particles influence biological interactions and mechanisms. In the cover image, particles with three different lengths are shown.

Recent progress in applying electrospun nanofibers to regenerative medicine is reviewed by Younan Xia and co-workers on page 10. Following a brief introduction to electrospinning, they discuss how scaffolds are fabricated from electrospun nanofibers with well-controlled compositions, structures, and alignments. Applications of the scaffolds in four specific areas are highlighted: nerves, dural tissues, tendons, and the tendon-to-bone insertion site.

An efficient thermal ablation agent was developed by confining gold nanoshells into nanopores of silicon microparticles. On page 84, Mauro Ferrari and co-workers show how near-infrared laser light triggers enhanced heat generation of gold nanoshells, by exploiting nanoscale cooperative effects inside microparticles. A multifold increase in thermal therapy efficacy was achieved for breast cancer in cell culture and in animal tumor models.

This Progress Report reviews recent progress in applying electrospun nanofibers to the emerging field of regenerative medicine. Following a brief introduction to electrospinning, it discusses how scaffolds are fabricated from electrospun nanofibers with well-controlled compositions, structures, and alignments. It then highlights applications of the nanofiber-based scaffolds in four specific areas that involve nerves, dural tissues, tendons, and the tendon-to-bone insertion site, respectively.

Bio-electrosprays and cell electrospinning have recently been shown benign for directly handling living cells and whole organisms in both in vitro and in vivo testing. In their Progress Report on page 27, Suwan N. Jayasinghe and coworkers review these approaches, which are the subjects of pre-clinical studies that validate new technologies on model organisms such as Xenopus tropicalis, shown in the image. (Image credits: T. J. Geach, L. B. Zimmerman, and S. N. Jayasinghe.)

Bio-electrosprays and cell electrospinning have recently been shown benign for directly handling living cells and whole organisms in both in vitro and in vivo testing. These biotechnologies are currently undergoing preclinical studies towards their utility in basic biology and the clinical sciences.

The effect of particulate physical properties on biological processes is a burgeoning research field. In this Review, the influence of geometry and mechanics on movement under flow conditions, biocirculation, and cellular adhesion and uptake are discussed. An emphasis is placed on the ultimate use of particles in biomedical applications.

Stimuli-sensitive polypeptide-based materials have recently received extensive attention. Polymeric materials, including micelles, vesicles, nanogels, and hydrogels, have been developed based on polypeptides with various structures and compositions. This Review focuses on recent intelligent polypeptide-based materials that have been designed and tested for controlled-delivery applications. In addition, the recent preparation of functionalized polypeptides is discussed.

The use of liquid marbles as micro-bioreactors for blood typing assays inside liquid marbles is explored by Wei Shen and co-workers on page 80. The haemagglutination reaction is initiated by injecting the relevant antibody into a marble of a blood sample. The reaction is signified by the separation of agglutinated red blood cells to the lower part of the marble, which leads to applications in ABO and Rh Blood typing.

A liquid marble micro-bioreactor is used to conduct blood typing as a typical biological assay. This study portrays the potential of using such microreactors for biochemical and biological analysis.

Hollow gold nanoshells are more efficient in heat generation triggered by near infrared laser when they are loaded into porous silicon particles, which results in effective cancer-cell killing in vitro and in vivo. Collective electromagnetic coupling of nanoconfined hollow gold nanoshells leads to dramatic enhancement of thermal ablation.

A highly sensitive, selective, and dual-readout (colorimetric and fluorometric) assay for acetylcholinesterase (AChE) based on Rhodamine B-modified gold nanoparticle is reported. Due to its good sensitivity and selectivity, the assay can be used for monitoring AChE levels in the cerebrospinal fluid of transgenic mice with Alzheimer's disease.

The remote heating of iron oxide nanoparticles in an alternating magnetic field is used to drive a thermoresponsive sol-gel block copolymer, Pluronic® F-127, through the upper phase transition temperature. This phase change triggers an accelerated release rate of a model drug. Actuation and return to baseline levels are demonstrated for multiple AMF doses.

In multi-interfacial polyelectrolyte complexation (MIPC), fusion of nascent fibers from multiple interfaces brings the interfaces to a point from which a composite fiber is drawn. MIPC applied to two, three, and four polyelectrolyte complex interfaces leads to various patterned multicomponent fibers. Cells encapsulated in these fibers exhibit migration, aggregation and spreading in relation to the initial cell or matrix pattern.

A novel and simple approach to prepare monodispersed chitosan microspheres with relative small size and controlled structures was developed by combining the solidification methods of solvent extraction and chemical crosslinking in a capillary-embedded microfluidic decive. The microspheres with different structures are used in the field of protein drug controlled release and immobilization lipases and they show different release profiles and good stability, respectively.

Anisotropic collagen fibrillogenesis is demonstrated within the pores of an accordion-like honeycomb poly(glycerol sebacate) tissue engineering scaffold. Confocal reflectance microscopy and image analysis demonstrate increased fibril distribution order, fibril density, and alignment in accordion-like honeycomb pores compared with collagen gelled unconstrained. Finite element modeling predicts how collagen gel and scaffold mechanics couple in matching native heart muscle stiffness and anisotropy.

In vitro studies of Staphylococcus aureus and Staphylococcus epidermidis proliferation on titanium with different roughness, porosity, topology and hydrophilicity are reported. Materials have been tested for human osteogenic and endothelial cell adhesion, proliferation, and differentiation. Results indicate the possibility of significanly decreasing the biofilm formation in comparison with non-optimized porous titanium coatings. This presents an opportunity to manufacture implants with intrinsic reduced infection risk, yet without additional use of antibacterial substances.