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Materials for biomedical applications are often chosen for their bulk properties. Other requirements such as a hemocompatible surface shall be fulfilled by suitable chemical functionalization. Here we show, that linear, side-chain methylated oligoglycerols (OGMe) are more stable to oxidation than oligo(ethylene glycol) (OEG). Poly(ether imide) (PEI) membranes functionalized with OGMes perform at least as good as, and partially better than, OEG functionalized PEI membranes in view of protein resistance as well as thrombocyte adhesion and activation. Therefore, OGMes are highly potent surface functionalizing molecules for improving the hemocompatibility of polymers., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

As shown in several studies, various properties of biomaterials such as stiffness, surface roughness, chemical composition or the amount of functional groups at the surface can influence adhesion, viability, proliferation and functionalities of cells. The aim of this work was to explore whether a cell-selective effect could be achieved for acrylonitrile-based copolymers containing different contents of positively charged functional groups, which were introduced by incorporation of methacrylic acid-2-aminoethylester hydrochloride (AEMA) units. The p(AN-co-AEMA) copolymers were synthesized by suspension polymerization in water and processed into disk shaped test specimen via a sintering process to ensure the absence of organic solvents in the copolymers. Copolymers with an AEMA content of 1.4, 1.6, and 4.4 mol-% were investigated according to their cell-selective capacity, which should support the adhesion, viability and proliferation of keratinocytes, while the adherence of fibroblasts should rather be disabled. The test samples were seeded with primary human keratinocytes and primary human dermal fibroblasts in mono- as well as in co-cultures. Tissue culture plate polystyrene (TCP) was used to control the physiologic growth of the cells. Density and viability of attached and non-adherent cells were analyzed by live/dead staining, lactate dehydrogenase (LDH) assay and flow cytometry with DAPI staining. For the assured discrimination of adherent cell types in coculture a keratin/vimentin-staining was performed. On copolymers with 4.4 mol-% AEMA adherent keratinocytes in monoculture and cocultured keratinocytes and fibroblasts showed a higher viability, a lower impairment of cell membranes and higher densities of viable cells compared to both other copolymers. For adherent fibroblasts these parameters did not differ between the copolymers and an increasing ratio of keratinocytes to fibroblasts in cocultures were found with increasing AEMA content. The results showed that keratinocytes and fibroblasts can be influenced by copolymers with different contents of positively charged functional groups. Since the tendency of a better adherence and viability of keratinocytes with increasing amounts of positively charged functional groups was shown, the potential enhancement by further increase of the amount of positively charged functional groups shall be tested in a future study.

Purpose: A system of nanoparticles with varying hydrophilicities may include promising biomaterial candidates as they offer various cellular uptake properties and a range of drug encapsulation efficacies, which would be advantageous in regenerative therapies. Therefore, a model system of nanoparticles with varying hydrophilicities was synthesized and assessed for its candidacy as a biomaterial., Methods: Here, acrylonitrile (AN) was copolymerized with N-vinylpyrrolidone (NVP) in a mini-emulsion to form a family of nanoparticles, thereby enabling the systematic variation of the copolymer hydrophilicity. The nanoparticles based on these copolymers were prepared and characterized using 1H-NMR, dynamic light scattering, differential scanning calorimetry, and thermal gravimetric analysis. Finally, the cytotoxicity of the nanoparticles was assessed by conducting indirect tests using L929 fibroblasts., Results: The nanoparticles showed well controlled NVP/AN molar ratios as determined by 1H NMR, well defined diameters ranging from approximately 100 nm to 200 nm, and increasing glass transition temperatures with increasing molar NVP content. Finally, L929 fibroblasts only slightly changed their morphology upon incubation with material eluates., Conclusions: Poly[acrylonitrile-co-(N-vinylpyrrolidone)] nanoparticles with varying amounts of NVP were shown to be a promising model system for further biological assessment.

Abstract: In this study, investigations on the protectiveness of poly(ether imide) coatings against corrosion of magnesium AZ31 alloy sheets are performed. The coatings were prepared in different pre-treated substrates by the dip coating method using N′N′-dimethyl acetamide (DMAc) and N′-methyl pyrrolidone solutions. The optimal performance was obtained for hydrofluoric acid treated substrates coated using DMAc solution (coating thickness 13μm) which showed impedances in the order of 107 Ωcm2 even after more than 3300h of exposure to a 3.5wt.% NaCl solution. This high performance is associated to an acid–base interaction at the interface as observed by X-ray photoelectron spectroscopy. [ABSTRACT FROM AUTHOR]

The corrosion behaviour of an AZ31 magnesium alloy coated with plasma electrolytic oxidation (PEO), polymer and a combination of them was assessed by electrochemical impedance spectroscopy (EIS) in 0·1M NaCl solution. The polymer coating was applied on a just cleaned surface (without any special preparation) and also on PEO treated magnesium substrate. While the polymer coated and the mere PEO treated magnesium alloy specimens lasted less than 50 h in the EIS tests, the specimens with the duplex coating (PEO+polymer) successfully resisted 1000 h in the EIS tests without showing any degradation. The improved adhesion of the polymer coating in presence of the PEO layer and the effective sealing of the pores in the PEO coating with the polymer were responsible for the enhanced corrosion resistance. The synergistic beneficial effect of the duplex coatings on the corrosion behaviour was also witnessed in the salt spray tests. [ABSTRACT FROM AUTHOR]