Development of Poloxamer Hydrogels Containing Antibacterial Guanidine-Based Polymers for Healing of Full-Thickness Skin Wound

A series of hydrogels containing guanidine-based polymers using a poloxamer as the matrix were prepared to provide novel wound dressings with antibacterial and repairing-promotion properties for skin wounds. Herein, we developed a series of antibacterial hydrogels, the cationic guanidine-based polymer polyhexamethylene guanidine hydrochloride (PHMG) with poloxamer aqueous solution (12%, w/w) simplified as PHMGP, chitosan (CS)-cross-linked PHMG (referred to as PHMC) with poloxamer aqueous solution simplified as PHMCP, and hyaluronic acid (HA)-modified PHMG (referred to as PHMH) with poloxamer aqueous solution simplified as PHMHP, for enhancing full-thickness skin wound healing. The characterizations, anti-microbial activity, cytotoxicity, and in vivo full-thickness wound-healing capability of these hydrogels were analyzed and evaluated. The results show that though PHMGP possesses great bactericide properties, its cytotoxicity is too strong to support skin regeneration. However, after modified with CS or HA, PHMCP and PHMHP showed good biocompatibility and antimicrobial properties against Gram-positive and Gram-negative bacteria that are commonly present in injured skin. Both PHMCP and PHMHP hydrogels exhibited upgraded wound-healing efficiency in full-thickness skin defects, characterized by a shorter wound closure time, faster re-regeneration, and the earlier formation of skin appendages, compared with those of control or pure poloxamer treatments. Their biological mechanism was detected. Both PHMCP and PHMHP can regulate the related biofactors during the skin repair process such as interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), transforming growth factor beta-1(TGF-beta 1), alpha-smooth muscle actin (alpha-SMA), and vascular endothelial growth factor, to promote wound healing with less serious scarring. In short, hydrogels with excellent capabilities to inhibit microorganism infection and promote wound healing were developed, which will shed light on designing and producing wound dressings with promising applications in future.