Surface-Adaptive Gold Nanoparticles with Effective Adherence and Enhanced Photothermal Ablation of Methicillin-Resistant Staphylococcus aureus Biofilm

Biofilms that contribute to the persistent bacterial infections pose serious threats to global public health, mainly due to their resistance to antibiotics penetration and escaping innate immune attacks by phagocytes. Here, we report a kind of surface-adaptive gold nanoparticles (AuNPs) exhibiting (1) a self-adaptive target to the acidic microenvironment of biofilm, (2) an enhanced photothermal ablation of methicillin-resistant Staphylococcus aureus (MRSA) biofilm under near-infrared (NIR) light irradiation, and (3) no damage to the healthy tissues around the biofilm. Originally, AuNPs were readily prepared by surface modification with pH-responsive mixed charged zwitterionic self-assembled monolayers consisting of weak electrolytic 11-mercaptoundecanoic acid (HS-C10-COOH) and strong electrolytic (10-mercaptodecyl)trimethylammonium bromide (HS-C10-N4). The mixed charged zwitterion-modified AuNPs showed fast pH-responsive transition from negative charge to positive charge, which enabled the AuNPs to disper...