Functional bacterial cellulose nanofibrils with silver nanoparticles and its antibacterial application.

Bacterial cellulose (BC) with good biocompatibility and superior mechanical properties has broad applications. BC functionalized with silver nanoparticles (AgNPs) has been assessed as an antimicrobial membrane for wound-healing treatment. During the AgNPs synthesis, avoiding the use of toxic chemicals is very necessary for the development of environmentally friendly procedures. Herein, a Komagataeibacter xylinus-based direct biosynthetic method to fabricate D-Saccharic acid potassium salt (SA)-grafted BC (SABC) through in situ bacterial metabolism was firstly explored. Subsequently, the SABC pellicles were immersed in AgNO solution for ion-exchanged process, and the silver nanoparticles (AgNPs) with diameter of ∼25.2 nm were in situ synthesized on SABC nanofiber surfaces by thermal reduction instead of using a reducing agent. The morphology and microstructure of SABC/AgNPs pellicles were analyzed by field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectra. Moreover, antibacterial activity measurement performed against the Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) by disk diffusion and plate count methods, showed high-efficiency bacteria-killing performance of SABC/AgNPs pellicles. This work proposed a new method by using microbial metabolism to prepare BC pellicles with functional groups, and antimicrobial films containing AgNPs was prepared by thermal reduction, exhibiting valuable prospects in wound healing treatment.