Wet-adhesive, haemostatic and antimicrobial bilayered composite nanosheets for sealing and healing soft-tissue bleeding wounds.

Healing soft-tissue wounds with an irregular, complicated topography in a bleeding environment demands the development of a dressing that is wet-adhesive, haemostatic, and antibacterial. To meet this unmet demand, we designed a flexible nanosheet (~77 nm thick) made of two layers, one is the antibacterial and haemostatic gelatin modified with dopamine (DA) and antimicrobial peptide (AMP) and mixed with Ca ions as coagulation factors, and another is the mechanically strong polycaprolactone (PCL). This flexible nanosheet exhibited robust mechanical strength, continuous and effective adhesion to a topographically irregular tissue surface under a wet condition, and a high platelet adhesion capacity. Moreover, the nanosheet presented a significantly reduced clotting time of 4 min and a high bactericidal rate of nearly 100%. An in vivo evaluation of the nanosheet using both murine dorsal skin and liver models further revealed that the nanosheet could successfully seal and heal the wounds in a bleeding environment, efficiently control haemorrhaging, and exert an excellent antibacterial effect in two weeks. Our work suggests that this nanosheet holds great promise in healing the bleeding soft-tissue wounds for treating acute trauma.