An injectable self-healing coordinative hydrogel with antibacterial and angiogenic properties for diabetic skin wound repair

AbstractWe report here an injectable, self-healing coordinative hydrogel with antibacterial and angiogenic properties for diabetic wound regeneration. The hydrogel was prepared by coordinative cross-linking of multi-arm thiolated polyethylene glycol (SH-PEG) with silver nitrate (AgNO3). Due to the dynamic nature of Ag-S coordination bond and bacteria-killing activity of Ag+, the resultant coordinative hydrogel featured self-healing, injectable and antibacterial properties. In this study, we synchronously loaded an angiogenic drug, desferrioxamine (DFO), in the coordinative hydrogel during cross-linking. We finally obtained a multifunctional hydrogel that is manageable, resistant to mechanical irritation, antibacterial and angiogenic in vitro. Our in vivo studies further demonstrated that the injectable self-healing hydrogel could efficiently repair diabetic skin wounds with low bacteria-infection and enhance angiogenic activity. In short, besides diabetic skin wound repair, such dynamic multifunctional hydrogel scaffolds would show great promise in the regeneration of different types of exposed wounds, in particular, in situations with disturbed physiological functions, high risk of bacterial infections, and external mechanical irritation.Wound repair: Self-healing materials step up to save feetSoft gels that can be injected into wounds to protect them from infection and promote blood vessel formation may benefit diabetic foot care. To create a scaffold-like substance tough enough to handle the mechanical stresses that feet experience, Hao Chen and colleagues from the Shanghai Jiao Tong University and Jiangsu University in China linked polyethylene glycol chains together using silver–sulfur chemical bonds that quickly re-join after being broken. This strategy produced a gel that returns to its original shape after being sliced or twisted, and which can be loaded with drugs to aid vascular network growth. Experiments in rat models revealed that direct injection of drug-containing gels to wounds decreased their size by 20% compared to control groups. The intrinsic antibacterial nature of silver ions also generated sterile inhibition zones around gel-treated lesions.In this work, an injectable, self-healing hydrogel with antibacterial and angiogenic abilities was prepared based on the coordination of multi-arm thiolated polyethylene glycol (SH-PEG) with antibacterial silver ions (Ag+). The injectable and self-healing properties derive from the dynamic nature of the Ag-S coordination bonds. After incorporation of an angiogenic drug desferrioxamine (DFO), we could obtain a multifunctional hydrogel with manageable, resistant to external stress, antibacterial and angiogenic properties. Such unique multifunctional hydrogel thus shows potential to accelerate the healing of some exposed wounds (e.g., diabetic skin wound) under disturbed physiological functions, high risk of bacterial infections, and external mechanical irritation.