Utilization of immunogold labeling to compare the adsorption behavior of fibrinogen, fibronectin and albumin on polymers.

Immunogold labeling followed by scanning electron microscopy (SEM) was used to examine the surface distribution of adsorbed plasma proteins. Adsorption was performed under various conditions on six different polymers; [low density polyethylene (PE), chromic acid-oxidized PE (OXPE), solution grade Biomer (SB), Teflon-(FEP), a laboratory synthesized polyurethane containing some zwitterions (ZW) and a polydimethylsiloxane based polyurethane (ZS) also containing zwitterions]. The proteins used were purified human and canine fibrinogen, fibronectin, and serum albumin. The immunogold staining technique was successful in the labeling of the adsorbed proteins. The adsorbed proteins were distributed differently on the polymers selected. Human and canine fibrinogen were found to cover all surfaces in a dense, uniform fashion. Albumin covered most surfaces in a less uniform fashion and on the zwitterionomers covered only a portion of the surface, leaving large bare patches. Fibronectin appeared to deposit unevenly, forming a network on part of the surface and uniformly coating other parts.