Improved osteogenesis and angiogenesis of theranostic ions doped calcium phosphates (CaPs) by a simple surface treatment process: A state-of-the-art study

Surface treatment of biomaterials could enable reliable and quick cellular responses and accelerate the healing of the host tissue. Here, a series of calcium phosphates (CaPs) were surface treated by hydrogen peroxide (H 2 O 2 ) and the treatment effects were physicochemically and biologically evaluated. For this aim, as-synthesized CaPs doped with strontium (Sr 2+ ), iron (Fe 2+ ), silicon (Si 4+ ), and titanium (Ti 4+ ) ions were sonicated in H 2 O 2 media. The results showed that the specific surface area and zeta potential values of the surface-treated CaPs were increased by ~50% and 25%, respectively. Moreover, the particle size and the band-gap (Eg) values of the surface-treated CaPs were decreased by ~25% and ~2–10%, respectively. The concentration of oxygen vacancies was increased in the surface-treated samples, which was confirmed by the result of ultraviolet (UV), photoluminescence (PL), Commission Internationale de l'éclairage (CIE 1931), and X-ray photoelectron spectroscopy (XPS) analyses. In vitro cellular assessments of surface-treated CaPs exhibited an improvement in cytocompatibility, reactive oxygen species generation (ROS) capacity, bone nodule formation, and the migration of cells up to ~8%, 20%, 35%, and 13%, respectively. Based on the obtained data, it can be stated that improved physicochemical properties of H 2 O 2 -treated CaPs could increase the ROS generation and subsequently enhance the biological activities. In summary, the results demonstrate the notable effect of the H 2 O 2 surface treatment method on improving surface properties and biological performance of CaPs.