Self-assembled NIR-responsive MoS2@quaternized chitosan/nanocellulose composite paper for recyclable antibacteria

Paper products are widely used in daily life, while the lack of antibacterial activity has made them become some disease transmission media. Herein, we introduced NIR-responsive molybdenum disulfide nanosheets (MoS2) to endow nanocellulose paper antibacterial activity by electrostatic self-assembly with quaternized chitosan (QCS). Firstly, the MoS2 nanosheets were exfoliated and stabilized with QCS under ultrasonication. The strong coordination between QCS and MoS2 as well as the electrostatic attraction between QCS and cellulose nanofiber (CNF) helped to fabricate the MoS2@QCS/CNF composite paper. The MoS2@QCS/CNF composite paper exhibited excellent photothermal and photodynamic activity, achieving over 99.9% antibacterial efficacy against both E. coli and S. aureus, respectively. The hyperthermia induced by MoS2 accelerated the glutathione (GSH) consumption and the reactive oxygen species (ROS)-independent oxidative stress destroyed the bacteria membranes integrity, synergistically leading to the malondialdehyde (MDA) oxidation and protein leakage to inhibit the bacteria growth. Importantly, the self-assembled fibrous network incorporating with the photo-stable antibacterial MoS2 enabled the flexible composite paper with excellent mechanical strength and recyclability for long-term antimicrobial, possessing over 99.9% inhibition even after five cycles. No cell cytotoxicity was observed for the MoS2@QCS/CNF composite paper, suggesting the potential of composite paper for bacterial infection control.