The potential use of novel poly(sulfobetaine) copolymers as antibioadherent coatings was investigated using Pseudomonas aeruginosa as a model microorganism and human macrophages and 3T3 mouse embryonic fibroblasts. Two well-defined statistical copolymers with narrow molecular weight distributions were prepared by group transfer copolymerization of n-butyl methacrylate (nBuMA) with either 10 or 30 mol % 2-(dimethylamino)ethyl methacrylate (DMAEMA). Sulfobetainized nBuMA-DMAEMA copolymers (poly[sulfobetaine-stat-nBuMA]) were obtained by treating these precursor polymers with 1,3-propanesultone under mild conditions. Both proton NMR spectroscopy and elemental microanalyses indicated that essentially all the DMAEMA residues were derivatized in both copolymers. Poly(methyl methacrylate) (PMMA) discs were coated with the sulfobetainized nBuMA-DMAEMA copolymers and the bioadherent properties of these coated materials were compared with those of PMMA. Statistically significantly fewer (p<.05) bacteria, macrophages, and fibroblasts adhered to the poly(sulfobetaine-stat-nBuMA)-coated PMMA than to the uncoated PMMA. The poly(sulfobetaine-stat-nBuMA) copolymer containing the higher proportion (30 mol %) sulfobetainized DMAEMA residues proved to be the more effective antibioadherent coating. The antibioadherent properties of these coating materials may allow the cost-effective production of dirt-resistant, easy to clean work surfaces, bioinert coatings for medical devices, and antifouling coatings for marine, agricultural, and industrial applications.

Bacterial adhesion to silver-coated orthopedic external fixation pins was compared with stainless steel controls in an in vitro study. Using five bacterial isolates from wound infections, the silver coating was found to reduce adhesion for Escherichia coli, Pseudomonas aeruginosa, and two strains of Staphylococcus aureus while the converse applied for Staphylococcus haemolyticus. When placed in human serum, both surfaces were conditioned to a similar extent with serum proteins; this conditioning lead to further reductions in bacterial adhesion, ultimately approaching similar levels for both stainless steel and silver-coated samples.

No abstract

No abstract

The adsorption of alpha-1-microglobulin (alpha-1-m) from serum to the surface of polymers with different physicochemical properties was investigated. Enzyme-linked immunosorbent assay showed binding of this protein to the surface of polystyrene (PS), polyvinyl chloride (PVC) and a polyurethane, Chronoflex, after water washing, but only trace levels could be detected on two polymethacrylate derivatives, polymethyl methacrylate and poly(2-hydroxyethyl methacrylate). alpha-1-m was selectively desorbed from the five materials by sequential washes of serum-conditioned surfaces with isopropanol solutions at increasing concentrations. The presence of alpha-1-m in the washing supernatants was detected by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The relative binding strength of alpha-1-m to each surface was evaluated as the isopropanol (IsoPOH) concentration required to desorb the protein from that surface. Analysis of bound proteins by SDS-PAGE conclusively demonstrated the binding of a range of serum proteins, including alpha-1-m, to all polymer systems, but with varying binding strengths. The majority of protein was removed by water washing for the polymethacrylate polymers, while varying concentrations of IsoPOH were required to desorb proteins from PS, PVC and Chronoflex. There was a correlation between the hydrophobic nature of the material, determined by water contact angle measurements, and adsorption of alpha-1-m. Immunoblotting of isopropanol-eluted proteins by alpha-1-m antibodies showed the positive staining of a 29 kDa protein as well as selected bands within a molecular weight range of 40 200 kDa, suggesting the adsorption of this protein as both free and complexed forms. The ability of alpha-1-m to adsorb on to material surfaces and to participate in events relevant to the biocompatibility of a polymer, such as bacterial infection or inflammation control, suggests the need for further characterization of the properties of this protein.