pH-Responsive Swelling Micelles for the Treatment of Methicillin-Resistant Staphylococcus aureus Biofilms

Biofilm formation exacerbates the challenge of eradicating drug-resistant bacterial infections. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major pathogens that leads to biofilm infections of the skin and soft tissue and device-associated infections. Here, we report a pH-responsive micelle that swells while releasing the loaded antibiotic, ciprofloxacin, in the low pH environment of MRSA biofilms. The antibiotic-loaded micelles were found to be more effective at eliminating MRSA biofilm bacteria and biofilm supernatant bacteria compared to treatment with free ciprofloxacin or pH-responsive micelles without encapsulated antibiotics. Blank pH-responsive micelles exhibited either comparable or greater reduction in MRSA biofilm bacteria burden compared to biofilms treated with only ciprofloxacin. Overall, our studies demonstrate the promise of using pH-swelling nanoparticles for the treatment of biofilm bacteria.