Bilayered nanosheets used for complex topography wound anti‑infection

There is a consensus that the prevention of wound infection should be achieved in the following ways:(1)closing the wound to protect it from extra infection;(2)an antibacterial agent that could kill endogenous bacteria.However,existing bulk two-dimensional antibacterial materials show inefficient adhesion to wounds with complex morphology and thus cause the prevention of wound closure.Reducing the thickness of bulk two-dimensional materials to less than 100 nanometres endows them with great flexibility,which could allow them to adhere to wounds with complex morphology by only physical adhesion.Herein,a broad-spectrum and efficient antimicrobial peptide(AMP)was introduced to biocompatible methacrylated gelatine(GelMA)with multiple modification sites,which served as an inner antibacterial layer.After being combined with a biodegradable and good mechanical poly-l-lactide(PLLA)outer layer through plasma-treatment-assisted spin coating,we finally constructed bilayered antibacterial nanosheets with a thickness of approximately 80 nm.These bilayered nanosheets possess good adhesion to surfaces with complex topography and thus achieve better wound closure than other bulk two-dimensional materials.Moreover,this AMP-grafted conjugation shows minimal cytotoxicity compared with Ag^+antibacterial agents,and the antibacterial rate of nanosheets is dependent on the graft rate of AMP.We suggest that this bilayered antibacterial nanosheet might be an advanced anti-infection dressing for wound treatment in clinical settings.