Dynamic coordination hydrogel with simultaneous anti-infected and angiogenic activities for promoting infected wound healing

Skin tissue injury is a common occurrence in daily life. The healing of skin wounds involve complex processes that involves the synergistic interaction of multiple factors. Bacterial infection may cause serious complications during the healing process. Therefore, the repair of infected skin wounds remains one of the most significant clinical challenges, since vascular damage is frequently accompanied, which may prolong or even impede the healing process. In this study, an injectable dynamic coordination hydrogel incorporating both an antimicrobial peptide and an angiogenesis-promoting factor was developed to construct a favorable repair microenvironment for infected wounds. Natural gelatin and heparin were chosen as the primary material, and reversible metal-ligand interactions (Au-S) enable these hydrogels to exhibit self-healing capabilities. A broad-spectrum antimicrobial peptide (KKFEFEFEFEKK) and the proangiogenic vascular endothelial growth factor (VEGF) were well introduced into the hydrogel system through electrostatic and heparin-VEGF binding affinity, respectively. The anti-infected and pro-angiogenic microenvironment in hydrogel could effectively combat<i>Staphylococcus aureus</i>and<i>E. coli</i>both<i>in vitro</i>and<i>in vivo</i>. Additionally, it could significantly promote blood vessel growth, thereby facilitating a rapid skin recovery. This coordination-caused dynamic antibacterial and proangiogenic hydrogel, based on biomolecular electrostatic interactions and binding affinity, represents an effective approach for multifunctional biomaterial design and holds potential for the treatment of infected wounds and even regenerative medicine.