An Ultra-Small Osmium Clusters-Loaded Organosilica-Based Antibacterial Nanoagent for Efficient Infected-Wound Healing

Recently, nanomaterials with natural enzymatic activity and photothermal effect offer an alternative pathway to combat bacterial infections and the abuse of antibiotics. Unfortunately, the development of these reported antibacterial nanoagents is always hampered by insufficient enzymatic activity and low photothermal conversion efficiency. To address these issues, herein, novel ultra-small osmium clusters-loaded F127-organosilica micelles (Os@FOMs) are developed as antibacterial nanoagents for efficient infected-wound healing. The preparation of nanoagents mainly involves the confined sol-gel transition of thiol-containing silane coupling agent in the hydrophobic region of F127 micelles and subsequent self-reduction process of osmium salt in the thiols/disulfides-doped organosilica framework. As a promising candidate for bacterial-infected wound healing, Os@FOMs exhibit not only high photothermal conversion efficiency of 70% under 808 nm near infrared (NIR) irradiation, but also display peroxidase (POD)-like activity in acidic conditions, which together contribute excellent antibacterial ability in acidic bacterial infectious microenvironment. On the other hand, Os@FOMs possess good catalase-like effect in neutral or weak alkaline conditions, thus protecting normal tissues from the POD-like protocol with exogenous H2O2 damage for efficient wound healing. It is highly expected that the new noble metal@organosilica-based nanoagents present a promising paradigm to fight antibiotic-resistant pathogens. An ultra-small osmium clusters-loaded organosilica-based antibacterial nanoagent with high photothermal conversion efficiency of 70% under 808 nm NIR irradiation and pH-dependent multiple mimic-enzyme activities is designed and developed for efficient infected-wound healing. This work provides a promising insight and method to construct high-performance noble metal-based antibacterial agent to fight antibiotic-resistant pathogens.image