Efficacy of Irradiated Bioactive Glass 45S5 on Attenuation of Microbial Growth and Eradication of Biofilm from AISI 316 L Discs: In-vitro Study

Abstract

Bacterial infection associated with medical implants remains a serious and costly drawback with both temporary and permanent consequences. Recently, some bioactive glasses have been found to show the antibacterial effect when interacting with bacteria. This study assessed the antibacterial activity of the bioactive glass (B.G.) based on 45S5 bioactive glass before and after treatment with gamma irradiation against multi-drug resistant microorganisms commonly involved in osteomyelitis. 45S5 glass which was synthesized by a melting technique with particle size < 45 μm was characterized by optical absorption, optical band gap and Fourier Transform Infrared Spectroscopy (FTIR) before and after exposure to gamma irradiation. From the optical absorption, the optical band gap can be calculated. The antimicrobial activity of 45S5 glass irradiated at 25 and 50 kGy against some pathogenic strains was evaluated. The results revealed that irradiated 45S5 bioactive glass causes a reduction in the number of survivors of the tested strains rather than the non-irradiated one. The microbial counts decreased by increasing the pH. The results also indicated that the colony forming units (cfu) decreased by one log cycle in nutrient broth (NB) medium and three log cycles in simulated body fluid (SBF). Scanning electron microscopy showed cell shrinkage and membrane damage after exposure of the glass to irradiation. So, an alkaline pH and SBF media along with gamma irradiation are considered as the most preferable conditions affecting the antimicrobial activity of the irradiated 45S5 glass and have the ability to eradicate the biofilm produced by P. aeruginosa on AISI 316 L discs which are used in joint replacement.