Protein adsorption on blood-contacting medical devices leads to thrombosis and infection. Therefore, protein-resistant biomaterials have the potential to improve device safety and efficacy. Poly(ethylene glycol) (PEG) has been incorporated into biomaterials (e.g. silicones) to confer protein resistance, but its performance in vivo is limited. To improve protein resistance, we prepared PEG-silane amphiphiles with a siloxane tether and variable PEG segment length (m) (Figure 1). Surface-grafted coatings having similar graft densities were prepared on silica wafers to eliminate restructuring effects and compared to those based on �PEG-controls� (i.e. no siloxane tether) as well as �siloxane controls� (i.e. no PEG segment). While surface hydrophilicity of PEG-silane amphiphile coatings increased with PEG segment length, the �PEG-control� surface-grafted coating was the most hydrophilic and exhibited the greatest resistance to fibrinogen adsorption. Next, medical-grade silicone was bulk-modified with PEG-silane amphiphiles as well as the controls. While silicones modified with the �PEG-control� were hydrophobic, those modified with PEG-silane amphiphiles were more hydrophilic and demonstrated a high capacity to restructure at aqueous interfaces. These results indicate that the siloxane tether imparts PEG with an important ability to restructure to the surface of polymeric networks. It was also found that PEG segment length influenced surface restructuring, where silicones modified with PEG-silane amphiphiles of m=8 were the most hydrophilic.

Protein resistance and surface restructuring of PEG-silane amphiphiles with variable PEG segment lengths

247th National Meeting (2014)

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