Atomic force microscopic investigations of transient early-stage bacterial adhesion and antibacterial activity of silver and ceria modified bioactive glass

Abstract

Bioactive glass 58S (BG58S) is widely recognised for its bioactivity and antibacterial properties, making it a promising material for orthopaedic implant applications. This study investigates the effects of incorporating silver (BG58S-2.5Ag) and cerium oxide (BG58S-5C) into BG58S on early-stage bacterial adhesion and subsequent bacterial growth inhibition. Using a high-intensity ball milling approach, BG58S was modified with 5% cerium oxide (CeO₂) and 2.5% silver (Ag) nanoparticles to create homogeneous BG58S-2.5Ag and BG58S-5C nanocomposites. Custom-made biomineral probes were employed to measure the bacterial adhesion within one second of contact with Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, using Atomic Force Microscopy (AFM). The results demonstrated that BG58S-2.5Ag showed significantly stronger transient adhesion to bacteria compared to BG58S, leading to a more effective long-term antibacterial response. Additionally, it was observed that the antibacterial effect of Ag commenced within one second of contact. These findings indicate a potential correlation between the rate of bond strengthening and cell wall penetration. This study highlights the potential for enhancing the effectiveness of antibacterial implant surfaces for various biomaterial applications.

Graphical abstract