Facile Fabrication of Hyperbranched Polyacetal Quaternary Ammonium with pH-Responsive curcumin Release for Synergistic Antibacterial Activity

In the current global crisis of antibiotic resistance, persuit of an effective multi-pathway collaborative approach to enhance antibacterial activity is urgently needed. Here, a kind of hyperbranched polyacetal quaternary ammonium (Hyper-ace-QA) with efficiently antibacterial function were synthesized by a succession of efficient click strategies. The high molecular weights can be obtained just after UV irradiation for 3 h, and the grafting ratio can be easily adjusted through controlling solvent system, molar ratio, and temperature. Cytotoxicity studies indicated that Hyper-ace-QA had good biocompatibility and can be used as a potential antibacterial dressing. More importantly, after in situ encapsulation of bioactive curcumin drugs into the hyperbranched intramolecular cavities, the acid-liable acetal linkers within the hyperbranched backbone made the loading antibacterial drugs rapidly release with pH- or bacterial-responsive behaviors since many bacteria can produce acids at the infection site by the combined actions of immune response and bacterial metabolism. Therefore, the integration of quaternary ammonium characteristics and pH-triggered curcumin release could facilitate the antibacterial activity against gram-positive Staphylococcus aureus. This work represents a synergistic strategy on offering important guidance to rational design of multifunctional antimicrobial vehicles, which would be promising therapeutic alternatives for first aid treatment of wound infection in critical situations.