Biocompatibility of electroactive polymers in tissues

The biocompatibility of ethylene-vinyl acetate copolymer (EVAc), polyethyle ne (PE), and polyaniline (PANi) films in the emeraldine (EM), nigraniline ( NA) and leucoemeraldine (LM) intrinsic oxidation states were assessed throu gh subcutaneous implantation into male Sprague-Dawley rats beneath the dors al skin, for a period ranging from 19 to 90 weeks. Histological examination , interstitial pressure measurement, and X-ray photoelectron spectroscopy ( XPS) were employed to determine the biocompatibility of the polymers. The p olymers did not provoke inflammatory responses in the subcutaneous tissues over the entire implantation period. Characteristics features associated wi th tissue-implant incompatibility were not evident near the implantation. I nterstitial pressure was measured to evaluate the development of tissue. Lo w interstitial pressure readings on the region of implantation confirmed th e biocompatibility of these polymer types. The surface composition of the e lectroactive aniline polymers before and after the implantation was charact erized by XPS. (C) 2000 John Wiley & Sons, Inc.