Fabrication, characterization, tailored structure, and in vitro biocompatibility of hydroxyapatite hollow microspheres

Abstract Hydroxyapatite (HAp) hollow microspheres are one of the most promising bio‐ceramics because of their excellent biocompatibility, strong osteo‐conductivity, and hollow structure. In this study, a simple method was proposed to fabricate HAp hollow microspheres by directly sintering the HAp/gelatin microspheres at high temperature. Scanning electron microscopy observations showed that HAp/gelatin microspheres had a dense structure, while HAp microspheres had a hollow structure. The sintering process not only caused the removal of gelatin, but also led to a structural transformation from dense HAp/gelatin microspheres to HAp hollow microspheres. The analyses of X‐ray diffraction patterns and Fourier transform infrared spectroscopy spectra indicated that HAp hollow microspheres were composed of apatite phase. Shell thickness of HAp hollow microspheres was increased with increasing the HAp/gelatin weight ratio. In vitro biocompatibility evaluation indicated that HAp hollow microspheres supported adhesion and proliferation of osteoblast MC3T3‐E1 cells, having potential as biocompatible cell carriers.