One–step synthesis of silver nanoparticles by lignocellulose nanofibrils to obtain antimicrobial hydrogels with accelerated wound healing

Lignin–containing cellulose nanofibrils (LCNF) have attracted extensive attention in the field of antibacterial due to the properties both of lignin and nanofibrils. The evenly distributed nano–lignin in LCNF can reduce Ag+, and the fiber network structure of nanofibrils may prevent the sedimentation of silver nanoparticles (AgNPs), which makes LCNF promising candidates for one–step preparation and deposition of AgNPs. Herein, carboxylated lignocellulose nanofibrils (CLCNF) with high stability were used to initiate the redox reaction. AgNPs (∼10.45 nm) were successfully prepared and homogeneously anchored onto CLCNF (Ag–L NPs–CLCNF). After compositing with polyvinyl alcohol (PVA) and tetracycline hydrochloride (TH), Ag–L NPs–CLCNF constructed a reversible redox quinone/catechol chemistry, imparting hydrogels with long–lasting reproducible adhesion and antimicrobial activity. Moreover, the incorporation of Ag–L NPs–CLCNF significantly improved the tensile strength (30.87 kPa), compressive strength (368.11 kPa) and thermal stability of the hydrogels, and that the Ag–L NPs–CLCNF hydrogel were self–healing. Importantly, the hydrogel containing Ag–L NPs–CLCNF can realize the controlled delivery of TH, giving it excellent antibacterial activity with accompanied good biocompatibility and significantly promoting full–thickness skin wound healing. This work offers a novel idea for preparing antibacterial hydrogels from lignocellulosic nanofibrils and the hydrogels have great application prospects in wound dressing.