Antimicrobial hydrogel with multiple pH-responsiveness for infected burn wound healing

Burns are a common medical problem globally, and wound infection is one of the major causes of inducing related complications. Although antibiotics effectively prevent wound infections, the misuse of antibiotics has created a new problem of superbugs. Herein, we propose a new strategy to obtain pH-responsive antimicrobial P-ZIF (ZIF: zeolitic imidazolate framework) by loading polyhexamethylenebiguanide (PHMB) into the framework of ZIF-8 nanoparticles. This will enable PHMB to be released in the weak acid environment of an infected wound. To address burn infections, P-ZIF nanoparticles were loaded into a hydrogel system made of sodium alginate (SA) and 3-aminophenylboronic acid modified human-like collagen (H-A) through borate ester bonds. The resulting H-A/SA/P-ZIF (HASPZ) hydrogel dressing not only possesses antibacterial and wound healing properties but also has dual pH responsiveness to prevent the overuse of medication while effectively treat deep second-degree burns. Therefore, P-ZIF nanoparticles and the corresponding HASPZ hydrogel dressing are considered of significant importance in antimicrobial, drug delivery, and wound repair.