Injectable, self-healing and pH responsive stem cell factor loaded collagen hydrogel as a dynamic bioadhesive dressing for diabetic wound repair

As one of the serious complications of diabetes, diabetic ulcers induce several clinical problems. Although a variety of wound dressings are commonly employed, their role is too simple to integrate wound adaptation, therapeutics and effectiveness. To meet this comprehensive need, an injectable hydrogel (Col/APG) consisting of collagen and polyethylene glycol was prepared and loaded with umbilical cord stem cell factor (SCF) for the treatment of diabetic wounds. The physico-chemical properties of the Col/APG hydrogel, including rheology, self-shaping and self-healing, were demonstrated to adapt to the wound. After loading with the SCF, the adhesion strength of the resulting Col/APG + SCF hydrogel was enhanced to 17 kPa and it also showed favorable biocompatibility. A rapid cellular response, sufficient collagen deposition and marked neovascularization were observed in the whole cortex defect model of a diabetic rat after the Col/APG + SCF hydrogel was applied. Additionally, the skew toward M2 macrophages, credited with providing the anti-inflammatory function, also existed in both hydrogel groups. These findings suggested that the Col/APG hydrogel is a desirable scaffold and the Col/APG hydrogel loaded stem cell factor as a dressing is a promising treatment for diabetic tissue regeneration.