Photothermal Antibacterial Performance of Bio-Derived Polymer Composite Materials

In this study, we utilize a controlled cellulose nanofiber (CNF) platform to investigate how synthesis parameters of delaminated 2D MXene components influence cellular response, photothermal behavior, and antimicrobial activity of the resulting composite materials. Six Ti3C2Tx MXenes were synthesized, delaminated, and then integrated into a cellulose nanofiber network under identical loading and vacuum-filtration conditions. The resulting free-standing CNF-MXene composites supported metabolic activity over six days and, upon near-infrared irradiation, rapidly increased in temperature and effectively reduced planktonic and biofilm-associated Staphylococcus aureus. Importantly, antibacterial performance varied substantially among MXenes and could not be predicted from the final temperature reached after 120 sec of irradiation alone. The MXene synthesis and delamination route therefore emerges as an upstream design variable that simultaneously modifies surface composition and Ti chemical-state distribution, flake morphology, and photothermal kinetics, producing distinct antibacterial responses within an otherwise fixed CNF composite platform. These results establish a processing-structure-property relationship for rationally selecting MXene synthesis routes for embedding in externally activated antibacterial composites and demonstrate that nominally identical Ti3C2Tx phases cannot be treated as interchangeable functional nanostructures for biomedical applications.