Biological effects of apatite nanoparticle-constructed ceramic surfaces in regulating behaviours of mesenchymal stem cells.

Although calcium phosphate (CaP) ceramics have been originally defined as bioactive materials because a biologically active hydroxycarbonate apatite (HCA) layer can form on their surfaces, the biological effects of the as-grown HCA layers are far from understood. In particular, it is unclear whether the as-grown HCA nanotopography can mediate the osteogenic commitment of mesenchymal stem cells (MSCs). In this study, a systematic investigation was performed to investigate the formation and biological effects of HCA nanotopography on CaP ceramic surfaces. Experiments demonstrate that the hydroxyapatite phase-containing CaP ceramics tend to grow HCA nanoparticle-constructed nanotopography, which can mediate bone marrow MSCs to condensate and spontaneously differentiate toward osteogenic lineage. In addition, the biological evolution of MSCs adhered on such nanotopography is similar to intramembranous ossification. Our findings provide support for applications of wurtzite phase-containing CaP ceramics in regenerative medicine for hard tissues.