Peptide modified gold-coated polyurethanes as thrombin scavenging surfaces

Abstract

Thin layers of gold were deposited on polyurethane film and chemisorbed with three peptides having an N-terminal cysteine: Cys-Pro-Arg, Cys-(L)Phe-Pro-Arg, and Cys-(D)Phe-Pro-Arg. The ability of these surfaces to act as thrombin scavengers was evaluated. The peptides are related to the known thrombin inhibitor Phe-Pro-Arg chloromethyl ketone and were shown to have significant thrombin inhibitory activity in solution. Attachment of the peptides to gold was confirmed by water contact angle and X-ray photoelectron spectroscopy measurements. Thrombin adsorption from a buffer and plasma was investigated, and chromogenic substrate assays were carried out for thrombin activity on the surfaces and in the supernatant following adsorption. The data suggest that the peptide-modified surfaces are able to adsorb thrombin with high affinity from a buffer and that thrombin is taken up selectively from plasma. The Cys-(D)Phe-Pro-Arg modified surfaces showed particularly high affinity for thrombin. It was also found that the activity of thrombin adsorbed on the peptide surfaces was inhibited, and inhibition was greatest on the Cys-(D)Phe-Pro-Arg surface. We concluded that the peptide surfaces may have potential as antithrombogenic materials via their ability to scavenge and inhibit thrombin generated as a result of blood-material contact.

Cell adhesion peptide modification of gold-coated polyurethanes for vascular endothelial cell adhesion

“…The amounts compare well with those noted in other studies using peptides for surface modification of gold. 10,28 Similar to the results of Bensebaa et al, 27 chemisorption of the thiol did not result in a shift in the gold peak. In all cases a small carboxylic peak was noted on the modified surfaces compared to unmodified controls (Fig.…”

“…Blots for the surfaces are much less complex than for plasma itself. 25 Unlike the results of Sun et al, 10 however, significant amounts of protein were eluted from and detected on the gold surface. Albumin was noted on all of the modified surfaces as well as on the gold control.…”

“…Tidwell et al 9 used an alkane thiol system to study the effect of surface chemistry on interactions with bovine endothelial cells. Sun et al 10 studied the interactions of peptide-modified gold surfaces with thrombin. The results of these and other studies suggest that complex biologic systems can be studied by using thiol-modified gold surfaces, the well-defined surface character of which allows for the study of the effects of surface chemistry on biologic interactions.…”

Selective albumin-binding surfaces modified with a thrombin-inhibiting peptide

“…These activities are higher than those previously used by us [18,33] and the percentage of labelled to unlabelled protein used (20%) was similar to that described by others [17]. Moreover, these labelled solutions were prepared using the minimum cpm by mg of unlabelled protein necessary to detect at least 100 cpm per sample.…”

“…proteins) to be used as a biomaterials coating: (1) easier and less expensive production; (2) greater stability (longer shelf-life); (3) generally, lower immunogenicity [14]; (4) more controllable coupling to the surface [15]. Small synthetic direct thrombin inhibitor peptides containing the amino acid sequence D-Phe-Pro-Arg, which resembles the specific thrombin binding of human fibrinopeptide A [16], have also been explored [17][18][19]. The small peptide, D-Phe-Pro-Arg-Pro-Gly (fPRPG) [20], which was previously immobilized by us onto ethylene glycol (EG)-terminated selfassembled monolayers (SAMs), inhibited the activity of adsorbed thrombin in a concentration-dependent way but lost most of its thrombin-binding selectivity in the presence of plasma proteins [18].…”