Improved biological compatibility of carbon materials via aqua regia and CaCl2 treatments

Abstract

In order to improve the bioactivity of three single-phase carbon materials (resin, pyrocarbon and graphite), chemical modification with aqua regia and CaCl2 solution was used to modify their original surfaces. The bioactivity of materials before and after modification was evaluated by in vitro apatite formation in simulated body fluids (SBF). The results showed that –COOH and Ca2+ were introduced on the sample surface by the chemical modification. The treated resin demonstrated the strongest ability to form a uniform and dense HAP coating after soaking in SBF for its largest specific surface area and the highest content of -COO-. The bone-like apatite coating demonstrated remarkably enhanced in vitro biocompatibility as indicated in the mouse fibroblast (L929) direct contact and ultrastructure observation. The transformation process of hydroxyapatite morphology in functional carbon materials, and the hydroxyapatite formation mechanism were systematically analyzed.