In vitro evaluation of the inflammatory potential of the silk fibroin

Silk fibroin membranes recently have been suggested as matrices for biomedi cal applications,,such as guided tissue regeneration and burn wound dressin gs. The aim of this study was to evaluate the inflammatory potential of fib roin films and to compare the fibroin films with two model materials with c ompletely different physico-chemical properties: poly(styrene) and poly(2-h ydroxyethyl methacrylate). Fibroin bound lower levels of fibrinogen than di d the two synthetic polymers while the same amounts of adsorbed human plasm a complement fragment C3 and IgG were detected. Studies of the binding stre ngth of C3 to fibroin, evaluated by a novel experimental procedure, indicat ed the occurrence of strong hydrophobic interactions at the interface. The activation of the mononuclear cells by fibroin, measured as interleukin 1 b eta production,was lower than the reference materials. Adhesion experiments showed the ability of the macrophages to adhere to fibroin by filopodia wi thout a complete spreading of the cells. The results achieved in this study demonstrate that the interactions of fibroin with the humoral components o f the inflammatory system were comparable with those of the two model surfa ces while the degree of activatiorr and adhesion of the immunocompetent cel ls appeared more limited. (C) 1999 John Wiley & Sons, Inc. J Biomed Mater R es, 46, 382-389, 1999.