Broad-Spectrum Light-Activated Synergistic Antibacterial Platform Based on an Azobenzene–Quaternary Ammonium@MXene Nanocomposite

To address the global public health challenge of bacterial infections, this study developed a broadband-responsive nanoantibacterial composite material named TAB AZO-GA-MXene (TAGM). The material was prepared by electrostatically loading cationic azobenzene quaternary ammonium salts onto the surface of the two-dimensional nanomaterial MXene, with gum Arabic (GA) used as a dispersant. The antibacterial properties of the composite material exhibit distinct variations following irradiation across a broad spectrum of light, including ultraviolet, visible, and near-infrared wavelengths. TAGM combines the physical shearing and photothermal effects of MXene with the membrane-disrupting and DNA-damaging capabilities of azobenzene quaternary ammonium salts, thereby establishing a multimechanism synergistic antibacterial platform. Experimental results show that the Trans form of TAGM demonstrates stronger bactericidal activity against <i>E. coli</i> under green light, whereas the Cis form exhibits better inhibitory activity against <i>S. aureus</i> under ultraviolet light. Under corresponding illumination conditions, TAGM achieved bacterial inactivation rates of 99.11% against <i>E. coli</i> and 99.81% against <i>S. aureus</i>, indicating rapid and highly efficient antimicrobial performance. This study not only broadens the spectral response range of light-responsive antibacterial materials but also provides a strategy for developing selective, multimechanism synergistic antibacterial systems, showing promising potential for combating multidrug-resistant bacterial infections.