Needle-Shaped ZnO/ZIF-L Hydrogel System for Bacterial pH-Responsive Detection and Synergistic Physical Disruption/Photodynamic Inactivation

Bacterial susceptibility testing and real-time inactivation are critical for safeguarding public health with broad applications in food safety monitoring and clinical diagnostics. For pH-dependent bacterial determination and hyperthermal inactivation applications, we developed needle-shaped ZnO/ZIF-L systems through a zeolitic imidazolate framework coating of zinc oxide by a self-template strategy. The pH-dependent ZnO/ZIF-L-embedded hydrogels were prepared by UV light-mediated olefin photopolymerization using acrylamide, <i>N</i>,<i>N</i>'-methylenebis(acrylamide), hydroxyethyl methacrylate, bromothymol blue (BTB), and ZnO/ZIF-L. The hydrogel achieves rapid visual detection of bacterial infections through a pH-responsive colorimetric transition, leveraging BTB to signal acidic microenvironmental shifts characteristic of bacterial proliferation. The ZnO/ZIF-L photosensitizers can enhance charge separation and transfer and generate highly reactive oxygen species. <i>Escherichia coli</i> and <i>Staphylococcus aureus</i> can be effectively inactivated for ZnO/ZIF-L hydrogels by a physical disruption/photodynamic synergistic antibacterial mechanism. The antibacterial efficiency can reach as high as 99%. The proposed strategy not only provides a sensitive strategy for bacterial determination but also implements efficient inactivation of bacteria simultaneously. This strategy combines real-time bacterial biosensing with on-demand antimicrobial action in a single platform, overcoming the limitations of conventional sequential detection-treatment approaches.