In situ formed collagen-hyaluronic acid hydrogel as biomimetic dressing for promoting spontaneous wound healing

Wound dressing is distinctly important to wound healing, because it can not only protect wound from external disturbance, but also provide an ideal environment for wound closure. However, most of wound dressings need additional active ingredients to assist the repair process. In order to develop new dressings that can present spontaneous healing activity, herein, an injectable hydrogel consisted of collagen I and hyaluronic acid has been designed to mimic extracellular matrix for vascular cells growing and wound closure. The preparation of hydrogel (COL-HA) was realized through in situ coupling of phenol moieties of collagen I-hydroxybenzoic acid (COL-P) and hyaluronic-acid-tyramine (HA-Tyr) through horseradish peroxidase (HRP). The physical structure and properties were characterized, and the biological performances were analyzed. COL-HA hydrogel presented porous structure that contributed to the exchange of gas, medium and nutrition. Human microvascular endothelial cells (HMEC) and fibroblasts (COS-7) cultured within this hydrogel showed significant proliferation behaviors. More importantly, a certain level of vascular endothelial growth factor (VEGF) was observed in HMEC cultured hydrogel, which led to the possibility of vascular regeneration. For the full-thickness wound, the healing ratio and validity of wound treated with COL-HA hydrogel were higher than commercial drug and individual COL-P hydrogel, HA-Tyr hydrogel groups, since collagen and hyaluronic acid made joint efforts to improve wound repair.