Positively Charged Aggregated Iridium Oxide Nanoparticles as a Delivery Platform to Combat Drug‐Resistant Bacteria

Abstract

Pathogenic bacteria represent a serious threat to public health, and antibiotic therapy remains a major approach for combating bacterial infections. However, the increasing prevalence of drug resistance among pathogenic bacteria has greatly compromised treatment efficacy. Although ursolic acid (UA) possesses various biological activities, its therapeutic application is severely restricted by poor solubility. A positively charged iridium oxide aggregated nanoparticle platform (IOA) was prepared, which was designed to function as both a UA delivery vehicle and a phototherapeutic agent. Under 808 nm NIR irradiation, reactive oxygen species (ROS) and heat were produced by IOA. The antibacterial efficacy of IOA@UA against Methicillin‐resistant Staphylococcus aureus (MRSA) was greatly enhanced upon NIR irradiation, even at a UA dose of only 20 µg mL − 1 , a concentration far below the reported minimum inhibitory concentrations (MICs) of S. aureus and MRSA, and the survival rate of bacteria was reduced to 58.8%. These results collectively indicate that the combination of UA chemotherapy with IOA‐mediated phototherapy represents an effective strategy against drug‐resistant bacterial infections.