Development of Anti-Fouling Materials for Blood-Contacting Devices
Abstract
The safety and efficacy of blood-contacting medical devices is hindered by thrombosis upon implantation in the body. Silicones and polyurethanes (PUs) are commonly used for hemodialysis catheters and other blood-contacting medical devices. However, due to their hydrophobic surfaces, they are susceptible to biological adhesion, including that of blood proteins and platelets that eventually result in thrombosis leading to device failure. Thus, this work explores the addition of a surface-modifying additive (SMA) into both silicones and PUs for their capacity to increase surface hydrophilicity. These SMAs are poly(ethylene oxide) (PEO)-silane amphiphiles comprised of an oligo(dimethyl siloxane) tether, a PEO segment, and a triethoxysilane crosslinking group. Several key parameters were investigated, including the concentration-dependent effects of these SMAs on water-driven restructuring and solvent selection for film fabrication. Using contact angle analysis, systematically prepared film compositions were evaluated for their ability to undergo water-driven surface restructuring to result in a hydrophilic, PEO-enriched surface. The SMA modified PU system was further analyzed in air- and water-equilibrated environments to evaluate its long-term efficacy in regard to water-driven restructuring, water-induced mass loss, and water uptake. The results demonstrated that silicones modified with PEO-silane amphiphiles were unaffected by solvent choice and able to restructure at concentrations as low as 10 μmol SMA/g of silicone. Similarly, for PU modification, PEO-silane amphiphile concentrations at 10 μmol SMA/g of PU or greater resulted in substantial water-driven restructuring that was maintained after 2 weeks of air-equilibration. After 2 weeks of water-equilibration, both mass loss and water uptake were minimal; however, restructuring capacity diminished slightly, and only PU samples with 25 μmol SMA/g of PU or greater, maintained hydrophilic surfaces. Overall, these results show the potential for PEO-silane amphiphile SMAs to enhance the protein resistance and thromboresistance of both silicone- and PU-based blood-contacting medical devices.
Subject
antifouling materialsPEO-silane amphiphile
polyurethane
silicone
surface modifying additives
SMA
Citation
Lim, Kendrick K (2019). Development of Anti-Fouling Materials for Blood-Contacting Devices. Undergraduate Research Scholars Program. Available electronically from https : / /hdl .handle .net /1969 .1 /194466.