Selenium-substituted hydroxyapatite particles with regulated microstructures for osteogenic differentiation and anti-tumor effects

Abstract

Abstract Selenium-substituted HA (Se/HA) particles with special micro/nanohybrid morphologies were prepared hydrothermally. With increasing Se substitution, Se/HA transitioned from a ribbon-like morphology, to a radical form, and further to microspheres (diameters: ∼10 μm) assembled from nanosheets (thickness: 2–5 μm; length and width: ∼100 nm). Chemical analyses confirmed increasing incorporation of Se in Se/HA particles, with increasing Se/(Se + P) molar ratio of the raw materials for their synthesis. Rat calvarial osteoblasts (RCOBs) adhered and spread on the Se/HA particles with Se/(Se + P) ratios ranging 0–0.05. Particles synthesized at Se/(Se + P) = 0.05 showed increased alkaline phosphatase activity of bone marrow mesenchymal stem cells, likely due to their micro/nano-sized surface morphology. Se released from particles effectively inhibited human osteosarcoma cell growth by inducing apoptosis. Therefore, Se/HA prepared at Se/(Se + P) = 0.05 presented a potential material for bone defect repair after surgical tumor removal, offering safety, increased osteogenic differentiation of stem cells, and inhibition of tumor cell growth. These results also suggest that trace element substitution is an effective approach to simultaneously imparting desirable microstructures and biological functions to bio-ceramics.