Tannic acid and silicate-functionalized polyvinyl alcohol-hyaluronic acid hydrogel for infected diabetic wound healing

Healing of chronic diabetic wounds is challenging due to complications of severe inflammatory microenvironment, bacterial infection and poor vascular formation. Herein, a novel injectable polyvinyl alcohol-hyaluronic acid-based composite hydrogel was developed, with tannic acid (TA) and silicate functionalization to fabricate an 'all-in-one' hydrogel PTKH. On one hand, after being locally injected into the wound site, the hydrogel underwent a gradual sol-gel transition in situ, forming an adhesive and protective dressing for the wound. Manipulations of rheological characteristics, mechanical properties and swelling ability of PTKH could be performed via regulating TA and silicate content in hydrogel. On the other hand, PTKH was capable of eliminating reactive oxygen species overexpression, combating infection and generating a cell-favored microenvironment for wound healing acceleration in vitro. Subsequent animal studies demonstrated that PTKH could greatly stimulate angiogenesis and epithelization, accompanied with inflammation and infection risk reduction. Therefore, in consideration of its impressive in vitro and in vivo outcomes, this 'all-in-one' multifunctional hydrogel may hold promise for chronic diabetic wound treatment.