In vitro preparation and ellipsometric characterization of thin blood plasma clot films on silicon

The wound-healing process around implants differs from that of a normal hea ling without the inserted material. In this work, the composition of a natu ral wound surface was mimicked through clotting of a thin human blood plasm a film with approximate ellipsometric thickness of 100 nm onto differently pretreated silicon surfaces. Their stability was investigated by incubation s in sodium dodecyl sulphate (SDS) solutions. The enzymatic clot degradatio n was induced through addition of human tissue plasminogen activator (t-PA) to the plasma and the surface protein remnants after the degradation were analyzed with polyclonal antibodies. The results show that the plasma films were not SDS resistant on hydrophilic silicon. However, stability was obta ined after preparation on hydrophobic silicon or when albumin or fibrinogen was immobilized to silicon before the plasma incubations. Different surfac es bound different polyclonal antibodies after the clot film degradation. T he methods indicate a simple means to improve or reestablish a normal tissu e inflammatory response around biomaterials. (C) 2001 Elsevier Science Ltd. All rights reserved.