Biocompatibility of novel polymer-apatite nanocomposite fibers

On the basis of the bioactivity of hydroxyapatite (HA) and the excellent mechanical and biocompatible performance of polyethylene terephthalate (PET), composite microfibers made of nanograde HA with PET was designed and fabricated to mimic the structure of biological bone, which exhibits a composite of nanograde apatite crystals and natural polymer. The PET/HA nanocomposite was molded into fibers so that the bulk structures' mechanical properties can be custom tailored by changing the final 3D orientation of the fibbers. This study focused on the in vitro biocompatibility evaluation of the PET/HA composite fibers as potential bone fixation biomaterial for total hip replacement prosthesis surfaces. The MTT assay was performed with the extracts of the composite fibers in order to evaluate the short-term effects of the degradation products. The cell morphology of L929 mouse fibroblast cell line was analyzed after direct contact with the fiber scaffolds for different time periods, and the cell viability was also analyzed by the Alamar Blue assay. The release of the inflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), from RAW 264.7 macrophages in the presence of fiber extracts and fibers was used as a measure of the inflammatory response. The ability of the fiber matrices to support L929 attachment, spreading, and growth in vitro, combined with the compatible degradation extracts and low inflammation potential of the fibers and extracts, suggests potential use of these fibers as load-baring bone fixation biomaterial structures.