Antibacterial activity of photothermal gold nanorods combined with antimicrobial peptides

Abstract

Biomaterials, used in medical implants for example, are important tools in modern medicine to ensure health and quality of life. Despite their benefits, biomaterials currently face two major problems, the difficulty of treating persistent biomaterialassociated infections and the rapid increase in bacterial antimicrobial resistance. It can be concluded that there is an urgent need for development of biomaterials able to prevent biomaterial-associated infections without relying on conventional antibiotics. Promising solutions are the implementation of antibacterial surface modifications of biomaterials and the use of antimicrobial peptides. The focus of this thesis was to perform in vitro evaluation of a material modification combining the antibacterial activity of surfaces functionalised with photothermal gold nanorods (AuNRs) in the presence of antimicrobial peptides (AMPs). The evaluation was performed by antimicrobial susceptibility testing, agar plate models and fluorescence microscopy. Significant antibacterial activity could be observed when irradiating AuNRs with near-infrared light in the presence of AMPs when tested against Staphylococcus aureus. A slight synergistic relationship between the AuNRs and AMPs could be observed, but further testing is needed to confirm the effect. This thesis provides important insight into the antibacterial activity of surfaces functionalised with photothermal AuNRs when in the presence of AMPs.