Effects of manganese and copper co-doped bioactive glasses with photothermal response on osseous cells

Herein, a series of bioactive glasses with a composition based on SiO₂Na₂OCaO-P₂O₅-Bi₂O₃, doped with either manganese (Mn) or copper (Cu), or a combination of both have been developed. The aim was to create a biocompatible, bioactive material with a photothermal (PT) response for potential use in bone cancer treatment. UV/vis/NIR spectroscopy indicated that the addition of Cu to the glass resulted in a broadband absorption of around 800 nm, while Mn showed an absorption band of around 500 nm. Photoluminescence (PL) spectroscopy, which was performed by exciting the specimen using a 750 nm beam, revealed an emission at 823 nm for all glass compositions, but with varying intensities. When exposed to an 808 nm laser (5 W/cm²), the glass samples exhibited temperature rising, with the sample containing both Mn and Cu, showing the highest absorption peak, reaching 204 °C after 5 min. The degradation rate of the glass in a phosphate-buffered saline (PBS) solution was influenced by the presence of Mn and Cu. Cytotoxic assessment on osteoblast-like cells showed that the presence of Mn promoted cell proliferation by over 20 % after 24 h, but when irradiated with an 808 nm laser, the viability of cells decreased by nearly 60 % due to heat ablation. Finally, the glass sample demonstrated in vitro bioactivity through the formation of a hydroxyapatite layer on its surface when immersed in simulated body fluid.