Functional composite nanofibers of poly(lactide–co-caprolactone) containing gelatin–apatite bone mimetic precipitate for bone regeneration

Functional nanofibrous materials composed of gelatin–apatite–poly(lactide–co-caprolactone) (PLCL) were produced using an electrospinning process. A gelatin–apatite precipitate, which mimicked bone extracellular matrix, was homogenized in an organic solvent using various concentrations of PLCL. A fibrous structure with approximate diameters of a few hundred nanometers was successfully generated. Apatite nanocrystallines were found to be effectively distributed within the polymeric matrix of the gelatin–PLCL. The addition of a small amount of gelatin–apatite into PLCL significantly improved the tensile strength of the nanofiber by a factor of 1.8. Moreover, tissue cell growth on the composite nanofiber was enhanced. Osteogenic differentiation of the cells was significantly stimulated by the composite nanofiber compared with the pure PLCL nanofiber. When implanted in a rat calvarium for 6 weeks the composite nanofiber supported defect closure and new bone formation better than the pure PLCL nanofiber, as deduced from micro-computed tomography and histological analyses. Based on these results, the gelatin–apatite–PLCL composite nanofiber developed in this study is considered to be potentially useful as a bone tissue regeneration matrix.