Promotion of wound healing by a thermosensitive and sprayable hydrogel with nanozyme activity and anti-inflammatory properties

The rapid healing of wounds requires strategies that relieve oxidative stress resulting from overloaded free radicals and which promote angiogenesis, collagen deposition, and re-epithelialization of the wound. Nickel ions have been reported to be correlated with angiogenesis. However, several applications of metal salts or oxides to wounds lead to increased toxicity. The nickel metal-organic framework (Ni MOF) nanorods described herein can slowly release nickel ions, resulting in reduced toxicity and improved wound healing rates. More importantly, the Ni₃(2,3,6,7,10,11-hexaiminotriphenylene)₂ (Ni₃(HITP)₂) nanorods with well-defined structures, superior conductivity and many catalytic sites showed superoxide dismutase (SOD)-like enzyme activity and scavenged various free radicals. In addition, the Ni₃(HITP)₂ nanomaterials contributed to promotion of the migration of fibroblasts, angiogenesis and macrophage polarization from M1 to M2. The aqueous solution of Pluronic F127, a temperature-sensitive, nontoxic and phase-changing hydrogel material, was shown to be an effective choice for injectable and sprayable medical dressings. The Ni₃(HITP)₂ MOF nanomaterials can be effectively encapsulated with the F127 hydrogel to achieve continuous long-term therapeutic effects. The toxicity test results suggested that the Ni₃(HITP)₂ MOF nanomaterials exhibited excellent biosafety and no observable toxicity or side effects in mice. Therefore, the Ni₃(HITP)₂ MOF nanorods hold promising potential in the biomedical field, and this work provides an effective solution to wound therapy.