An enzyme-responsive and photoactivatable carbon-monoxide releasing molecule for bacterial infection theranostics

Infections caused by pathogenic bacteria, especially the drug-resistant bacteria, are posing a devastating threat to public health, which underscores the urgent needs for advanced strategies to effectively prevent and treat these intractable issues. Here we report a feasible and effective theranostic platform based on an enzyme-sensitive and photoactivatable carbon monoxide releasing molecule (CORM-Ac) for the successive detection and elimination of bacterial infection. The extracellular bacterial lipase can trigger the excited state intramolecular proton transfer (ESIPT) via elimination of the ester group in CORM-Ac, thus providing a fluorescence switch for an early warning of infection. Subsequently, the potent bactericidal therapy against the model bacterial strains, Staphylococcus aureus (S. aureus) and notorious methicillin-resistant Staphylococcus aureus (MRSA), was readily realized via photoinduced release of CO. In addition, the CORM-Ac and CORM showed good biocompatibility within a wide range of concentrations. The results of an infected animal wound test also demonstrated that the CORM-Ac-loaded gauze was effective in indicating the wound infection and accelerating the wound healing via the photoinduced CO release. The simplicity, functional integration, good biocompatibility and broad adaptability make CORM-Ac very attractive for bacterial theranostic applications.