Tight binding of albumin to glow discharge treated polymers

Abstract

Tetrafluoroethylene (TFE) glow discharge-treated Dacron vascular grafts resist thrombus deposition, embolization and thrombotic occlusion. In addition, albumin adsorbed on TFE-treated surfaces resists elution by sodium dodecyl sulfate (SDS). Since the tight binding of albumin to TFE-treated surfaces may contribute to their thromboresistant character, we decided to examine the mechanism responsible for this tenacious adsorption. We have investigated albumin adsorption and retention (after SDS elution) on a number of untreated and glow discharge-treated surfaces. Fluorocarbon glow discharge-treated polymers retain a larger fraction of the adsorbed albumin than ethylene and hexamethyldisiloxane glow discharge-treated surfaces. Albumin retention by surfaces appears to be closely related to their surface free energy (in air). Low energy surfaces (in air), whether untreated or glow discharge-treated, retain a larger fraction of the albumin adsorbed than higher energy surfaces. The lowest energy surfaces should have the highest interfacial energies in water, with correspondingly high driving forces for adsorption of proteins. This can lead to the formation of multiple binding sites upon adsorption, permitting strong hydrophobic interactions, which leads to the observed strong binding.