A 3D-printed gelatin based dual-crosslinking composite dressing loaded with puerarin to enhance wound healing in diabetes

An ideal dressing for wound healing and skin infection treatment should possess multifunctional properties, including air permeability, antibacterial activity and the capability to accelerate the wound healing process. Herein, a gelatin methacryloyl (GelMA) based fiber–hydrogel composite dressing loaded with N-halamine antibacterial agent 1-chloro-2,2,5,5-tetramethyl-4-imidazolinone (MC) and puerarin was successfully constructed by electrospinning (EP) and 3D printing technique. Notably, the product of the combination of electrospinning and 3D printing cannot only form a barrier between wound area and external environment but also provide the air exchange channel for cell regeneration at the wound site. Additionally, the designed matrix endows the dressings with an outstanding swelling ratio and blood-clotting capability, while the introduction of N-halamine and puerarin equips the dressings with strong antibacterial and anti-inflammatory activity. The MC-based N-halamine dressings exhibit excellent antibacterial efficiency through “N-Cl”, and over 99.0 % of S. aureus and E. coli O157:H7 were killed within 30 min of contact with G-3D/EP-MC@Pue. The wound closure rate treated with G-3D/EP-MC@Pue reached 60.31 % after 8 days of healing, and many hair follicles were visible in the G-3D/EP-MC@Pue group on day 16 (23.0 ± 1.8/mm 2 ). The in vivo wound healing results indicated that the G-3D/EP-MC@Pue dressing could prevent infection and promote skin tissue regeneration, demonstrating the promising potential of G-3D/EP-MC@Pue dressings for diabetic wound healing.