Synthesis and characterization of Ag-doped 45S5 bioglass and chitosan/45S5-Ag biocomposites for biomedical applications

This paper approaches the synthesis and characterization of pure (45S5) and Ag-doped (45S5-Ag) bioglasses obtained through the sol-gel method and the development of chitosan/45S5-Ag biocomposites, followed by their performance evaluation as biomaterial candidates. The bioglasses were made from the precursors of tetraethyl orthosilicate (TEOS), triethyl phosphate (TEP), calcium nitrate tetrahydrate, and sodium carbonate. Silver nitrate at the concentrations of 5 and 10% was used as the doping agent. The gel production was followed by a drying process at 60 degrees C for 24 h, and then, heat treatment at 700 degrees C was carried out for 2 h. Next, the bioglass powders were added to a chitosan solution at the concentration of 80% ww(-1). The solutions were lyophilized before and after neutralization. The samples were characterized via TG, DTA, DSC, DRX, FTIR, SEM, OM, biodegradation, cytotoxicity, and antibacterial activity. Through TG, the increase in silver percentage in the bioglass resulted in lower mass loss of biocomposites, while for DSC higher thermal stability of the polymeric phase was observed for the doped samples. The biological assays demonstrate that CB5 and CB10 samples present inhibition activity against gram-positive and gram-negative bacteria. Both CB5 and CB10 can be almost entirely degraded by phosphate-buffered saline in 28 days and are not cytotoxic, which lays bare that these samples can be used for tissue regeneration.