Cell responses to biomaterials IV: in vitro and short-term in vivo investigations of the biocompatibility of sponges of a perfluorosulphonated polymer, ethylene:vinyl acetate copolymer, silicone rubber and porous polytetrafluoroethylene

Abstract

The in vitro and in vivo cell and tissue responses to two novel biomaterials, namely sponges of ethylene:vinyl acetate copolymer (Elvax) tetrafIuoroethylene: perfluoro 3,6-dioxa-4-methyl-7-octenesulphonyl fluoride copolymer (Nafion) and to commercially available silicone rubber sponge (Silastic) and to expanded polytetrafluoroethylene (Goretex) have been evaluated. All four materials failed to elicit a cytotoxic response in vitro however varying degrees of stability and biocompatibilitywere observed in subcutaneous implants upto 12 weeks in mice. Nafion and Goretex were the most stable materials. However, Nafion generated a greater multinuclear giant cell response than did Goretex or Elvax. Elvax sponges were very slightly reduced in size over the 12-week period. Cell and tissue ingrowth were greatest over the period of study in Elvax sponges. Silastic sponges were broken down rapidly and elicited an inflammatory response which, most likely, was due to the presence of a soluble component of the sponge. These results suggest that Elvax, Nafion and Goretex are well tolerated in comparison to the preparation of Silastic sponge used in this study. The performance of Elvax and Nafion warrants further research into their use as biomaterials either as connective tissue replacements (in the form of sponges) or as components of other soft tissue prostheses.