The safety and efficacy of blood-contacting medical devices is often compromised due to surface-induced thrombosis. In order to reduce thrombosis, biomaterials must be largely protein resistant. When used to bulk-modify silicones and other polymeric biomaterials, the ability of poly(ethylene oxide) (PEO) to reduce protein adsorption critically relies on its migration to the water-surface interface. For this work, PEO-silane amphiphiles were prepared to improve the protein resistance of silicones by enabling rapid migration of PEO to the surface (<b>Figure 1</b>). Three PEO repeat segment lengths (m = 3, 8, and 16) were synthesized and tested in a medical-grade silicone at varying concentrations (5, 10, 25, 50, and 100 μmol per 1.0 g silicone). Surface-restructuring of PEO-silane amphiphiles in bulk-modified silicone was measured by temporal static water contact angle analysis. It was found that both PEO-silane amphiphile concentration and PEO-segment length played a significant role in surface restructuring. The amphiphiles with repeat unit length m = 3 showed a modest increase in surface hydrophilicity whereas the m = 8 amphiphiles demonstrated remarkable water-driven surface restructuring and subsequent hydrophilicity, even at low concentrations. The m = 16 PEO-silane amphiphiles also demonstrated significant restructuring, but required higher concentrations than m = 8. The impact of extended conditioning in water on surface-restructuring was also studied. Finally, adsorption of fibrinogen was also measured on modified silicones and it was observed that only the films that restructured extensively were effective in resisting protein adsorption.

Role of PEO-segment lengths in surface properties of antigouling PEG-silane amphiphile

249th National Meeting (2015)

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