Hydroxycarbonate apatite formation, cytotoxicity, and antibacterial properties of rubidium-doped mesoporous bioactive glass nanoparticles

Abstract

Rubidium (Rb) has been shown to impact biological activity. This work synthesized Rb-doped mesoporous bioactive glass nanoparticles (MBGNs) based on the composition 70SiO2–30CaO mol% with a sol-gel method. Rb2O was substituted for CaO in concentrations of 5 and 10 mol%. The influence of Rb incorporation on the hydroxycarbonate apatite (HCA) formation, cytotoxicity, and antibacterial capacity of particles was evaluated. XRD analysis confirmed the amorphous structure of the particles. In vitro, biomineralization studies showed HCA on the surface of MBGN and Rb-doped MBGN pellets after 7 days of soaking in simulated body fluid (SBF). An inhibition zone of Escherichia coli (E.coli) and Staphylococcus aureus (S. aureus) around Rb-doped MBGN pellets was detected, while MBGN pellets did not show any inhibition zone. Additionally, MC3T3-E1 pre-osteoblastic cells demonstrated cytocompatibility when exposed to Rb-MBG suspensions at different concentrations of up to 250 µg/ml. Based on their overall properties, Rb-containing MBGNs are proposed for biomedical applications, such as filler nanoparticles in composite bone scaffolds.