Biological activity of hydroxyapatite/poly(methylmethacrylate) bone cement with different surface morphologies and modifications for induced osteogenesis

Although having advantages such as good mechanical property and rapid curing, the poor absorption and biological activity of hydroxyapatite (HA)/poly(methylmethacrylate) (PMMA) bone cement limits its clinical application. Therefore, it is of vital importance to improve the integration and the biological activity of HA/PMMA bone cement. In this study, spherical and rod-like HA/PMMA bone cement with different content of P(MMA-co-MPS) were chosen to enhance its interface bioactivity. The content of P(MMA-co-MPS) on the surface of HA was 12, 30, 15, and 28%, respectively, corresponding to 0.3 r-HA, 1.5 r-HA, 0.3 s-HA, and 1.5 s-HA, whose calcium-to-phosphorus (Ca/P) ratios were 1.62, 1.5, 1.65, and 1.53, respectively, and were confirmed by energy dispersive spectroscopy. From scanning electron microscope, we found that the spherical HA (s-HA) promotes the biomineralization on the surface of PMMA than rod-like HA (r-HA). In addition, cell experiments in vitro showed that s-HA/PMMA with lower modification degree (0.3) of P(MMA-co-MPS) results in more cell adhesion and more evenly distributed on surface spreading while observed under laser confocal microscope. Meanwhile, in vitro, cell proliferation and alkaline phosphatase activity indicated that s-HA/PMMA bone cement promotes early osteogenic differentiation of rBMSCs in a deeper extent than r-HA/PMMA, demonstrating that 0.3 s-HA/PMMA provides a favorable theoretical basis for the further clinical application of HA/PMMA bone cement as an optimized bone repair material. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48188.