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.