Human serum albumin and fibrinogen interactions with an adsorbed RGD-containing peptide

The modification of polyethylene terephthalate (PET) and polytetrafluoroeth ylene (PTFE) with an arginine-glycine-aspartic acid cell adhesion peptide, RGD peptide (PepTite(TM) Adhesive Coating; Telios Pharmaceuticals, San Dieg o, CA) has been previously investigated. Initial animal studies showed this RGD peptide to accelerate healing and assist in the formation of an endoth elial cell lining of the lumenal side of PET and PTFE fabrics in a cardiova scular application. It is of interest to determine how this RGD peptide is able to influence cellular events through intervening layers of plasma prot eins that spontaneously adsorb upon implantation. This study examined the i nteraction of predeposited RGD-containing peptide with human serum albumin (HSA) or fibrinogen that was characterized using multiple attenuated intern al reflection infrared (MAIR-IR) spectroscopy, ellipsometry, and contact an gle analysis. It was determined that fibrinogen-containing films consistent ly exhibited more mass than films of the RGD peptide, HSA, or HSA adsorbed onto RGD peptide-containing films. MAIR-IR spectra of RGD peptide films bef ore and after HSA adsorption were similar in absorption and intensity; howe ver, ellipsometry indicated HSA introduction had created thicker, less dens e films. Fibrinogen, on the other hand, when adsorbed onto RGD peptide film s provided increased relative mass in a more compact arrangement. Contact a ngle analyses of each of the dried films showed their surface energies to r emain high, but the polar components of RGD peptide films were reduced afte r either serum protein adsorption. These phenomena may be related to the mi nimal thrombus accumulation that was noted during the initial animal studie s, that promoted subsequent healing. (C) 1999 John WiIey & Sons, Inc. J Bio med Mater Res, 46, 355-359, 1999.