Janus hydrogel with dual antibacterial and angiogenesis functions for enhanced diabetic wound healing

Anti-infection and neovascularization at the wound site are two vital factors that accelerate diabetic wound healing. However, for a wound healing dressing, the two functions need to work at different sites (inner and outer), giving big challenges for dressing design. In this study, we fabricated a novel sodium alginate/chitosan (SA/CS) Janus hydrogel dressing by the assembly of SA hydrogel loaded with silver nanoparticles (AgNPs) and CS hydrogel impregnated with l-arginine loaded sodium alginate microspheres (ArgMSs) based on electrostatic interactions to combine the two functions. The outer SA-AgNP hydrogel could prevent infection while avoiding the deposition of AgNPs in the wound site, and the inner CS-ArgMS hydrogel on the wound surface could realize the sustained release of l-arginine and promote vascular regeneration. The composition, morphology and swelling/degradation of the SA-AgNP/CS-ArgMS hydrogel were characterized systematically. l-Arginine release behavior has been tested and SA-AgNP/CS-ArgMS hydrogel has been confirmed for excellent biocompatibility. Antibacterial and angiogenesis assays demonstrated the antibacterial and angiogenesis characteristics of the SA-AgNP/CS-ArgMS hydrogel. Finally, in vivo diabetic wound healing assay demonstrated that the SA-AgNP/CS-ArgMS hydrogel could significantly accelerate re-epithelialization, granulation tissue formation, collagen deposition and angiogenesis, thereby resulting in enhanced diabetic wound healing