Macromolecular Bioscience

Cover: The ability of cardiac fibroblasts to sense the topography of their microenvironment varies with substrate stiffness. Stiffness and topography have an interactive effect on cell morphology and alignment. This paper demonstrates that 18 kPa topographically modified substrates optimally induce elongation and alignment of cardiac fibroblasts. Further details can be found in the article by S. Al-Haque, J. W. Miklas, N. Feric, L. L. Y. Chiu, W. L. K. Chen, C. A. Simmons, and M. Radisic* on page 1342.

Two-photon polymerization techniques and other methods are used to fabricate physically and/or biochemically well-defined synthetic 3D cell culture scaffolds. Single cell responses to geometrical, biochemical, and mechanical aspects of these tailored 3D environments are discussed.

Block copolymers of polylactide (PLA) and poly(trimethylene carbonate) (PTMC) with hydrophilic methoxyethoxyl groups are designed. The surface of the copolymer films are covered by PTMC segments due to the hydrophilicity of the methoxyethoxy groups, observed by XPS spectra. The results lead to the suppression of PLA degradation by proteinase K, as well as PTMC degradation by lipase due to the methoxyethoxy groups.

A cellular-uptake-shielding magnetic cell catcher is fabricated in the form of multifunctional microcapsules via LbL self-assembly. The microcapsules are capable of identifying specific target cancer cells due to the RGD recognition motifs, and of isolating the cancer cells efficiently with the aid of a magnetic field.

The antitumor activity of DOX-loaded ALG-PDEA NPs is evaluated both in vitro and in vivo through cell culture and animal models. It is found that the DOX-loaded ALG-PDEA NPs effectively suppress tumor growth compared with free DOX while at the same time reducing the side effects of DOX.

The nanofiber organization, achieved by deposition of random fibers on the uniaxially-aligned nanofiber mat in a gradient manner, directed morphological changes of applied adipose-derived stem cells, which could help mimic the structural orientation of complex biomechanical structures like the collagen fiber structure at the tendon-to-bone insertion site.

Most studies focusing on contact guidance use rigid patterned substrates. It is not known how the cell's ability to follow grooves and ridges changes as the substrate stiffness is decreased to the range found in native tissues. A significant interactive effect of substrate stiffness and topography on cardiac fibroblast elongation and orientation is demonstrated.

Storage tubes for biological material induce a side adsorption of neurodegenerative markers leading to their depletion. New inner surfaces of storage tubes are developed using a combination of plasma chemistry and grafting of a polymer-surfactant mixture. Their nonfouling properties are shown to depend on their surface charge and the surface texturing.

The synthesis and characterization of a new MRI-visible polymer is described. MR signal enhancement and gadolinium stability of coated meshes with DTPA-Gd-PMA are satisfying, even after sterilization. In vitro, the polymer does not induce a cytotoxic effect on fibroblasts. Moreover, the T₁ effect of the polymer allows an efficient and fast localization of coated meshes after implantation.

The pH sensitivity of a series of PbAEs based on primary amines is studied. A PEG-PolyA3 block copolymer is synthesized from mPEG-acrylate, 1-propylamine and 1,4-butanediol diacrylate. It has a rapid transition at around pH = 6.4. In vitro release and cell experiment studies show that it provides a potential pH-responsive nanocarrier for intracellular drug delivery.

An ultra-bright fluorescence probe comprising folate-conjugated polymer nanoparticles is developed for targeted cell imaging of FR over-expressing cancer cells. Highly blue fluorescent polyfluorene nanoparticles with negative surface charges are coated with a folate-conjugated cationic triblock copolymer. The coated PF-NPs exhibit efficient cell imaging for FR over-expressing KB cells.

Micro/nano-structures of different roughness formed by depositing gold NPs on planar gold films adsorb large amounts of proteins non-specifically, but inhibit L929 cell growth; however, after modification with POEGMA brushes via ATRP and further conjugation with GRGDY, the surface enhances L929 fibroblast-specific interactions while maintaining superior low-fouling properties.

Copolymers of NIPAAm and AEMA with low toxicity exhibit a thermo-switchable antibacterial effect which is more prominent toward Gram-negative than to Gram-positive bacteria. The effect is studied for copolymers in solution and a crosslinked non-leaching coating on cotton by different microbiological test methods regarding E. coli and B. subtilis.

Antifouling surfaces based on ω-oligo(ethylene glycol)alkanethiols and on polymer brushes of HOEGMA, HEMA, CBAA and HPMA are challenged with eight biofluids of interest for human and veterinary diagnostics and bioapplications. Among the excellent antifouling properties observed on brushes, poly(CBAA) and poly(HPMA) emerge as the only non-fouling surfaces.

Tough biodegradable shape-memory networks with good shape fixity and shape recoverability are prepared from high-molecular-weight D,L-lactide and trimethylene carbonate macromers. The glass transition temperature (T_g) defines the shape transition temperature. When T_g is close to body temperature, flexible devices that can be implanted minimal-invasively can be designed.

Loading of the low-molecular-weight water-soluble photosensitizer MB is achieved by heat-shrinkage of polyelectrolyte multilayer capsules. Most of the encapsulated MB molecules are stably retained for long time and protected by the capsule walls against reductive enzymes, and keep their photodynamic activity to effectively kill cancer cells under laser irradiation.