One-pot quaternization of dual-responsive poly(vinyl alcohol) with AIEgens for pH-switchable imaging and killing of bacteria

Facing the challenges posed by bacterial infection, the real-time detection of bacterial infection combined with antibacterial functions is urgently needed. Herein, we prepare thermo- and pH-responsive poly(vinyl alcohol) derivatives (PVA–TPE) bearing aggregation-induced emission luminogens of tetraphenylethene (TPE) and quaternary ammonium moieties through a facile one-pot quaternization with a tertiary amine method. Intrinsic fluorescence from TPE moieties and antibacterial functions from quaternary ammonium units can efficiently integrate the functions of “monitoring and killing of bacteria”. It is found that PVA–TPE can selectively image and kill Gram-positive bacteria at pH 7.4, while it switched to display enhanced broad-spectrum antimicrobial activity against both Gram-negative and -positive bacteria in an acidic environment (pH 5.5). Moreover, PVA–TPE exhibits low cytotoxicity on mammalian cells of L929, HepG2 and red blood cells. Furthermore, in vivo evaluations further confirmed that PVA–TPE has excellent antibacterial efficacy with no tissue damage. This study represents the first example of a pH-switchable integrated system for “monitoring and killing of bacteria” constructed through a facile one-pot quaternization method.