In Vitro Study of CaTiO3-Hydroxyapatite Composites for Bone Tissue Engineering

A biocomposite composed of hydroxyapatite (HAp) and CaTiO3 was fabricated to study the phase stability, mechanical strength, and biocompatibility for bone tissue engineering. To investigate the optimal concentrations for the biocomposite, different HAp concentrations (0%, 50%, 70%, and 100%) were mixed with CaTiO3 and sintered in a microwave furnace. X-ray diffraction patterns of CaTiO3/HAp composites indicated the phase stability of CaTiO3/HAp. Mechanical properties were characterized by Vickers hardness, Young modulus, fracture toughness, brittleness, and compressive strength. MC3T3-E1 cells were used for in vitro studies to investigate the biocompatibility of CaTiO3/HAp composites, using 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay and immunofluorescence. The in vitro studies confirmed the highest cell viability on 70HAp at 1, 3, and 7 days. Collagen Type I, osteopontin, and osteocalcin expressions were evaluated by Western blotting and a strong signal of collagen Type I and osteopontin expression was shown by cells grown on 70HAp and 100HAp. Interestingly, osteocalcin signal was found only on 70HAp at day 7. The expression of alkaline phosphatase and osteopontin confirmed that the 70HAp expressed the strongest fluorescent signal as compared with pure materials. Thus considering the biological properties, 70HAp biocomposite was found ideal for bone -tissue engineering.