Bactericidal and in vitro osteogenic activity of nano sized cobalt-doped silicate hydroxyapatite

Abstract

Hydroxyapatite (HA) particles with enhanced antibacterial properties can be prepared by integrating metal ions into the crystal structure of the nanoparticles. Cobalt and silicate ions containing HA (Co/Si-HA) with the formula Ca10-xCox(PO4)(6-y)(SiO4)(y)(OH)(2) (x = 0.2, 0.6, and 1.0 and y = 0.5) was successfully synthesised by using microwave-assisted wet precipitation method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and inductively coupled plasma mass spectrometry (ICP-MS) techniques were used to characterise the synthesised nanoparticles. The results revealed that the incorporation of SiO44- ions increased the lattice parameters and decreased the crystallite size of HA. However, the incorporation of Co(2+)ions led to the reduction of lattice parameters and the particle size of the SiHA nanoparticles. In vitro antibacterial activity of materials was evaluated using disk diffusion and minimum inhibitory concentration (MIC) protocols. The findings indicated that incorporating Co2+ ions into SiHA inhibited the growth of Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). The cytotoxicity of materials evaluated using the Sarcoma osteogenic (Saos-2) cell line revealed that they were cytocompatible and exhibited no adverse side effects. The osteogenic differentiation of cells was confirmed by the significant increase in the alkaline phosphatase (ALP) activity by incorporating Co2+/SiO44- ions into the HA crystal structure. Our results show that the nanoparticles prepared in this study have a promising future in biomaterial-tissue engineering applications.