Enhanced Antimicrobial\nEfficiency of Gold Nanoclusters\nvia Improved Sonodynamic Activity and Out-Membrane Crossing Capacity

Antimicrobial\nsonodynamic therapy (SDT) holds great promise\nin\nclinical practice regarding its noninvasiveness, high safety profile,\nand absence of resistance concern. However, exploring high-efficiency\nsonodynamic sensitizers is slow-moving and remains a big challenge.\nWe, herein, employed gold nanoclusters (Au NCs) as a novel class of\nsonodynamic sensitizers, demonstrating notable antimicrobial efficacy\nin treating infected wounds. Specifically, l-arginine (Arg)\nand 6-azido-2-thiothymidine (ATT) cocapped Au NCs featured enhanced\nstructural rigidity, suppressing nonradiative relaxation of excited\nelectrons and achieving a reactive oxygen species (ROS) yield exceeding\n45%. Moreover, the modification of ATT-Au NCs by Arg imparted amino\nacid-like properties to the Au NCs, while the ultrasound (US) up-regulates\nthe expression of <i>OmpF</i> porins in <i>E. coli</i>. This synergy resulted in a burst of ROS production within the bacterial\ncells, ultimately leading to a four-order-of-magnitude reduction in\nmicrobial viability.