Gallium nanoparticle as an antimicrobial agent to combat antibiotic resistance

Since they were first discovered, antibiotics have been used to fight bacterial infections and save millions of lives. However, their increased use has allowed for the development of antibiotic resistant pathogens, which reduces their efficacy and threatens the accomplishments of modern medicine. The development of a new agent represents a major unmet clinical societal need. Metals are increasingly becoming considered as an alternative antimicrobial agent, and gallium in particular has gained a lot of attention in recent years. Whilst their antimicrobial activity has been demonstrated against a variety of bacterial pathogens and biofilms, their translation into the clinical setting is partly hindered by its low bioavailability. To address this issue, this project aimed to use nanotechnology to develop gallium-based nano-formulations. Several synthesis methods, namely the heat-up method, hot-injection and flame spray pyrolysis were successfully used to synthesise different classes of gallium nanoparticle. The heat-up method produced gallium nanoparticles with low uniformity and was difficult to reproduce. As such, only hot-injection and flame spray pyrolysis synthesised gallium nanoparticles were further investigated for their antimicrobial activity and toxicity. Despite undetected minimum inhibitory concentrations, gallium nanoparticles showed activity towards biofilm. They altered biofilm morphology and reduced pyocyanin production, which relates to the pathogen’s virulence factor. The results indicate the potential of gallium nanoparticle for development as an antimicrobial agen