Bifunctional cellulose nanocrystal-MoS2 nanosheets for NIR-activated fluid management and antibacterial protection in wound microenvironments

Abstract

Responsive wound dressings that operate on the responsive mechanism of "external light stimulation-material photothermal conversion-local microenvironment regulation" are key for protecting wound surfaces, promoting healing, and providing antibacterial effects. This work presents an intercalated structure of cellulose nanocrystals (CNCs)/MoS₂ nanosheets through an innovative "exfoliation-functionalization" strategy. Additionally, CNC-MoS₂ nanosheets serve as highly effective photothermal fillers in polylactic acid (PLA) membranes for wound dressing. These membranes demonstrate excellent UV-blocking capabilities, superior moisture absorption, and good breathability. Remarkably, the membrane with 7 wt% CNC-MoS₂ achieves a 400% increase in moisture absorption, with a water vapor transmission rate (WVTR) of 1025 g/m²/day. The membranes also demonstrate excellent photothermal conversion capacity: under irradiation at 2 W/cm², the surface temperature of the membrane with a 7 wt% CNC-MoS₂ content increases by 25.8 °C. It remains stable in phosphate-buffered saline (PBS), demonstrating its potential for use in photothermal therapy within moist wound environments. Upon exposure to near-infrared (NIR) laser irradiation, the hybrid membrane exhibits enhanced antibacterial activity, resulting in 3 mm inhibition zones for both E. coli and S. aureus. The cell biocompatibility reaches 99.5% and migration rate reaches 51.2% after 24 h with NIR. This study provides a strategy for developing responsive wound dressings, offering an innovative solution for complex wound care.

Keywords: Antibacterial property; Cellulose nanocrystal-based nanosheets; Photothermal response; Wound dressing.