Lignin-Derived Gold–Titanium\nDioxide Nanophotocomposites\nas Potent Photoactivatable Probes for Microbial Inactivation

The overuse of antibiotics has accelerated antibiotic\nresistance,\nand it is a significant global threat to public health. To combat\nthe rising threat of drug-resistant microbes, antimicrobial photodynamic\ntherapy (APDT) has emerged as a promising alternative therapeutic\nstrategy. This study focuses on the synthesis of eco-friendly lignin-derived\ngold–titanium dioxide nanophotocomposites (L@Au-TiO<sub>2</sub> NCs). Lignin was utilized as a sustainable precursor for the synthesis\nof L@Au-TiO<sub>2</sub> NCs. The gold and TiO<sub>2</sub> nanoparticles\npossess inherent photodynamic properties, and thus the developed L@Au-TiO<sub>2</sub> NCs exhibit enhanced antimicrobial efficacy due to the synergistic\ncombination of their attributes. The antimicrobial potential of the\nL@Au-TiO<sub>2</sub> NCs was evaluated against various microbial strains\n(Escherichia coli, Bacillus\nmegaterium, and Candida tropicalis) under dark and green light conditions. The outcome of this study\nhighlights the promising potential of L@Au-TiO<sub>2</sub> NCs for\nphotodynamic antimicrobial applications. The L@Au-TiO<sub>2</sub> nanophotocomposites\ncould be explored in the fields of medicine and nanotechnology to\nintroduce innovative ideas into the biomedical field.