FIBRINOGEN ADSORPTION AND HOST TISSUE RESPONSES TO PLASMA FUNCTIONALIZED SURFACES

The physical and chemical characteristics of material surfaces are tho ught to play important roles in biomaterial-mediated tissue responses. To understand the importance of discrete biomaterial chemical charact eristics in modifying host tissue responses, we constructed surfaces b earing different functional groups using radio frequency glow discharg e plasma polymerization. Surfaces evaluated included those having high concentrations of -OH, -NH2, -CF3, and siloxyl groups. These surfaces and polyethylene terephthalate controls were used to assess the impor tance of particular physicochemical characteristics in surface:protein :cell interactions both in vitro and in vivo. The results obtained sho w that surface functionalities do significantly affect both the adsorp tion and ''denaturation'' of adsorbed fibrinogen (which is an importan t mediator of inflammatory responses to biomaterial implants). In addi tion, these surfaces provoke different degrees of acute inflammatory r esponses. Interestingly, the amounts of ''denatured'' fibrinogen that spontaneously accumulate on the individual surfaces correlate closely with the extent of biomaterial-mediated inflammation. These results su ggest that surfaces that tend to ''irreversibly'' bind fibrinogen prom pt greater acute inflammatory responses. Unexpectedly, all test surfac es except those bearing a siloxyl group engender relatively similar bi omaterial-mediated fibrotic responses. Thus surface functionalities al one may not be sufficient to affect subsequent fibrotic responses. (C) 1998 John Wiley Rr Sons, Inc.