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The modification of polyethylene terephthalate (PET) and polytetrafluoroethylene (PTFE) with an arginine-glycine-aspartic acid cell adhesion peptide, RGD peptide (PepTite Adhesive Coating; Telios Pharmaceuticals, San Diego, CA) has been previously investigated. Initial animal studies showed this RGD peptide to accelerate healing and assist in the formation of an endothelial cell lining of the lumenal side of PET and PTFE fabrics in a cardiovascular application. It is of interest to determine how this RGD peptide is able to influence cellular events through intervening layers of plasma proteins that spontaneously adsorb upon implantation. This study examined the interaction of predeposited RGD-containing peptide with human serum albumin (HSA) or fibrinogen that was characterized using multiple attenuated internal reflection infrared (MAIR-IR) spectroscopy, ellipsometry, and contact angle analysis. It was determined that fibrinogen-containing films consistently 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 before and after HSA adsorption were similar in absorption and intensity; however, ellipsometry indicated HSA introduction had created thicker, less dense films. Fibrinogen, on the other hand, when adsorbed onto RGD peptide films provided increased relative mass in a more compact arrangement. Contact angle analyses of each of the dried films showed their surface energies to remain high, but the polar components of RGD peptide films were reduced after either serum protein adsorption. These phenomena may be related to the minimal thrombus accumulation that was noted during the initial animal studies, that promoted subsequent healing.

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Mussel adhesive protein (MAP) is the adhesive agent used by the common blue sea mussel (Mytilus edulis) to attach the animal to various underwater surfaces. It is generally composed of 75 to 85 repeating decameric units with the reported primary sequence NH2‐Ala(1)‐Lys(2)‐Pro(3)‐Ser(4)‐Tyr(5)‐Hyp(6)‐Hyp(7)‐Thr(8)‐DOPA(9)‐Lys(10)‐COOH. This study examines this peptide's solution‐state conformation using proton nuclear magnetic resonance (NMR) spectroscopy. NMR and molecular modeling of the decamer before and after molecular dynamics calculations in water suggests a conformation that retains an overall bent helix. © Munksgaard 1997.

Mussel adhesive protein (MAP) from the marine mussel Mytilus edulis is considered to be responsible for attaching it to surfaces in its native environment. The isolated and partially purified form of MAP, marketed as 'Cell-TakTM' (BioPolymers, Inc., Farmington, CT), is currently being used as an in vitro aid for attachment of cells to culture vessels. The collective results reported here indicate that Cell TakT"' binds strongly to clean germanium plates, serving as surrogate substrata for those found in many natural situations. These 'conditioning films' become thicker with increasing applied concentration, which is typical of most proteins. This effectively masks the physical-chemical properties of the original solid surface from the cells, while expressing new adhesive properties for cell attachment, which might well be a recognition phenomenon related to specific functional groups and/or surface configuration of the protein. The data presented here show that polar surface energy component (Yp) values of -12 dynes/cm, in conjunction with critical surface tensions above -30 dynes/cm, are associated with concentrations near 2 p g/cm2 for maximal cell attachment.

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