Visible-Light-Triggered Self-Reporting Release of Nitric Oxide (NO) for Bacterial Biofilm Dispersal

Bacterial infection poses a massive threat to our society, and bacterial biofilm is a major cause of chronic and recurrent infections. The treatment of bacterial biofilms represents a challenging task, and the development of antibacterial materials that can not only disperse bacterial biofilms but also kill bacteria is of increasing interest. Herein, we report the fabrication of well-defined nitric oxide (NO)-releasing amphiphiles, poly(ethylene oxide)-b-polyCouNO (PEO-b-PCouNO), where CouNO is an N-nitrosoamine-based NO donor containing a coumarin chromophore, exhibiting visible-light-mediated and self-reporting NO-release behavior. Unlike conventional polymeric NO donors derived from N-diazeniumdiolate (NONOates) or N-nitrosothiol (SNOs) that could be only synthesized via the postmodification procedure due to poor stability, the newly developed N-nitrosoamine-based NO donors can be directly polymerized into amphiphiles using reversible addition-fragmentation chain transfer (RAFT) polymerization. The NO-releasing amphiphiles self-assembled into micelles and selective NO release in aqueous medium was achieved by irradiating the micelle solution with visible light, which was characterized by a remarkable fluorescence turn-on (>185-fold), thereby enabling in situ self-reporting NO release. The photoinduced NO release can efficiently disperse bacterial biofilm of Pseudomonas aeruginosa. Moreover, antibiotics (e.g., Ciprofloxacin, Cip) could be loaded into the NO-releasing micelles, and co-delivery of NO and Cip was achieved, allowing for simultaneous biofilm dispersal and bacterial killing. This work provides a new strategy to fabricate macromolecular NO donors, which can efficiently avoid uncontrolled NO leakage and display promising antibacterial applications.