Fabrication of nano-structured calcium silicate coatings with enhanced stability, bioactivity and osteogenic and angiogenic activity.

The bioactivity and stability of coatings on alloy implants play critical roles in the fast osseointegration and maintenance of a long-term life span of the implants, respectively. Herein, nano-sheet surface on bioactive calcium silicate (CaSiO3, CS) coatings on metal substrates was fabricated by combining atmosphere plasma spraying (APS) and hydrothermal technology (HT). The glassy phase in CS coatings generated by APS was converted into crystalline sheet-like nano-structures after HT treatment. Compared with the original CS coating samples, HT treatment decreased the degradation rate of the CS coatings. Moreover, the fabricated nano-structured topography of CS coatings increased the apatite mineralization ability and significantly enhanced the cell attachment, proliferation, differentiation, alkaline phosphatase (ALP) activity and expression of osteogenic genes and angiogenic factors of rat bone marrow stromal cells (bMSCs). Our results suggest that the nano-structured CS coatings have immense potential in improving the clinical performance of medical implants.