In-vitro antimicrobial & biocompatibility study of Spherical 52S4.6 Submicron-Bioactive glass synthesized by Stöber Method: Effect of Ag Doping

Bioactive glass has become a promising material due to its biocompatibility and bioactivity toward both soft tissue and hard tissue regeneration. In the present study, nearly monodisperse, dense and spherical shaped un-doped and Ag-doped 52S4.6 submicron bioactive glass (SBG) particles were synthesized using sol-gel method with one-step base condensation i.e., Stöber method using tetraethyl orthosilicate (TEOS), calcium nitrate tetrahydrate (Ca(NO 3 ) 2 •4H 2 O), triethyl phosphate (TEP), silver nitrate (AgNO 3 ) and sodium nitrate (NaNO 3 ) as precursors. The silver doping was performed at a concentration of 0.5 mole% and 1 mole% of total glass composition by changing the concentration of sodium nitrate in the bioactive glass network. The synthesized 52S4.6 SBG, both un-doped and Ag-doped powders showed predominately amorphous phase as suggested by the XRD data and indicated the presence of all the corresponding functional groups in the FT-IR spectra analysis. The synthesized powder exhibited spherical shape within the range of 448–671 nm as obtained from FE-SEM image. The synthesized 52S4.6 SBG elicited antimicrobial property against Staphylococcus aureus ( S. aureus ) and Escherichia coli ( E. coli ) at a concentration of 5 mg/ml and with an efficacy of 58.6% after 16 h incubation period. However, upon incorporation of Ag into the bioactive glass matrix efficacy in inhibiting the growth of S. aureus and E. coli was significantly enhanced to 99.6% and 99.2% with Minimum Inhibitory Concentration (MIC) of 10 mg/ml and 15 mg/ml, respectively at 0.5 mole% Ag-doped SBG at the same incubation interval. In-vitro cell culture study on biocompatibility and viability, namely live/dead assay and cell viability and proliferation assay such as MTT assay on MG-63 cell cultured Ag-doped and un-doped 52S4.6 SBG revealed that 0.5 mole% Ag-doped SBG exerted minimal cytotoxicity towards the cultured MG-63 cells. Graphical Abstract Highlights Monodispersed, and spherical-shaped 52S4.6 bioactive glass (SBG) particles were synthesized. 0.5 mol% Ag-doped 52S4.6 SBG showed excellent bioactivity. Minimum inhibitory concentrations for E.coli and S. aureus were 0.5 mole% Ag-doped 52S4.6 SBG at 10 mg/ml and 15 mg/ml, respectively.