Binary SiO2–CoO spherical bioactive glass nanoparticles for tissue engineering applications

Pro-angiogenic capabilities are desired for biomaterials intended for tissue repair and tissue engineering applications, and bioactive glass (BG) nanoparticles are good vehicles for the delivery of ions with therapeutic properties, such as cobalt, which displays a well-known angiogenic effect by mimicking hypoxic conditions by HIF-1α stabilization. In this work, novel monodispersed spherical dense BG nanoparticles were obtained by the sol-gel process with the incorporation of cobalt into the glass structure as a potential platform for the delivery of pro-angiogenic ions, and particles with sizes ranging from 93 to 112 nm were obtained. Structural evaluation showed that cobalt (II,III) oxide were formed and deposited on the particles’ surface, while X-ray photoelectron spectroscopy (XPS) analysis pointed that Co2+ ions were also incorporated in the glass as a network modifier. Glasses also displayed a rapid and sustained Co release when immersed in phosphate buffered saline, and MTT assay showed good cell viability for BG concentrations of 100 μg mL−1 and 500 μg mL−1, confirming its potential to be applied for tissue engineering. Therefore, this study showed that Co containing nanoparticles, with great potential for tissue repair with the release of pro-angiogenic ions, can be obtained by a simple sol-gel based method.