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Dynamic Whole Blood Study of Silicone Modified with PEO-Silane Amphiphiles
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Blood-contacting medical devices rapidly adsorb plasma proteins that initiate clot (i.e. thrombus) formation. Antithrombotic drugs may reduce clotting and associated device dysfunction and ischemia, but put the patient at risk for hemorrhaging. Silicone, a common blood-contacting device material is highly prone to protein adsorption and subsequent clotting due to its extreme hydrophobicity. Poly(ethylene oxide) (PEO), a hydrophilic polymer, is highly protein resistant but its function when incorporated into silicone depends critically on its presence at the silicone-water interface. To enable rapid and substantial migration of PEO to the silicone surface, a PEO-silane amphiphile [α-(EtO)3Si(CH2)2-ODMS13-block-PEO8-OCH3] was prepared that bears the ability to substantially reduce fibrinogen adsorption on silicone, even at low concentrations. This work comprehensively evaluated the thromboresistance of a silicone modified with the PEO-silane amphiphile via its exposure to whole blood under dynamic conditions using a Chandler Loop. Clotting was evaluated in terms of occlusion time and thrombus formation for silicones modified with varying levels of the PEO-silane amphiphile. Results demonstrated that concentrations as low as 10 mol of amphiphile per gram of silicone were able to significantly reduce platelet adhesion and prevent occlusion during the course of the study. This indicates that the amphiphiles are useful in preventing protein adhesion and obviating clot formation, increasing the safety and lifetime of implantable blood-contacting devices.
Barry, Mikayla E (2017). Dynamic Whole Blood Study of Silicone Modified with PEO-Silane Amphiphiles. Undergraduate Research Scholars Program. Available electronically from