Development of light-activable silver nanoparticles for the elimination of antibiotic-resistant bacteria and biofilm

With the rise in antibiotic resistance (AR) and multidrug-resistant (MDR) bacteria, there is a need for novel antimicrobials that can exert antibacterial action via multiple mechanisms. Nanoparticles such as silver nanoparticles (AgNP) can serve as a potential alternative due to their unique optical and physiochemical properties along with their innate broad-spectrum antibacterial activity. AgNPs antibacterial property is associated with the release of silver ions (Ag+), which is a slow process taking up to days to achieve effective antibacterial levels. Recent findings indicate that combining photodynamic inactivation (PDI) with AgNP shows antibacterial synergy. This research is aimed at developing light-activated silver nanoparticles and investigating their light-responsive Ag+ release kinetics to understand their role in antibacterial synergy.
Herein, protoporphyrin IX conjugated on the AgNP surface (PpIX-AgNPs) was developed and Ag+ release kinetics were investigated to correlate the Ag+ release kinetics to the antibacterial synergy of PS-AgNP. These PpIX-AgNPs serve as excellent light-activated antimicrobial agents and this antibacterial action was demonstrated in antibiotic-resistant bacteria (ARBs). The antibacterial action of this light-activated PpIX-AgNP was further modulated by adopting a dual-step irradiation strategy to ensure the controlled release of Ag+. Finally, this research includes a preliminary study demonstrating the transport of nanoparticles within biofilms and light-activated inhibition of Vibrio cholerae biofilms. This research provides crucial knowledge for designing light-responsive silver-based antimicrobials for potential wound-healing applications.