Thermosensitive PNIPAM-Based Hydrogel Crosslinked by Composite Nanoparticles as Rapid Wound-Healing Dressings

Chronic wounds are prone to produce excessive reactive oxygen species (ROS), which are the main reason for multiple bacterial infections and ulcers at the wound. Therefore, regulating ROS is the key in the process of wound healing. Herein, a new type of thermosensitive hydrogels is developed to improve the scavenging efficiency of ROS and accelerate wound repair. Nano-CeO₂ was uniformly dispersed on the surface of mesoporous silica (MSN). The nanocomposite particles were physically crosslinked with poly(N-isopropylacrylamide) (PNIPAM) to form a MSN-CeO₂@PNIPAM thermoresponsive hydrogel (PMCTH). The stability, temperature sensitivity, rheological properties, biocompatibility, and wound healing ability of the PMCTH were evaluated in detail. The results showed that the hydrogel could not only maintain the stability of the system for a long time with low biological toxicity but also have a phase transition temperature close to the human body temperature. In addition, the PMCTH was directly applied onto the skin surface. The MSN-CeO₂ nanoparticles would be dispersed in the hydrogel to restrict ROS exacerbation effects and promoted the formation of blood vessels as well as surrounding tissues, accelerating the wound healing. More importantly, animal experiments showed that when the mass ratio of CeO₂ to MSN was 40%, the wound healing rate reached up to 78% on the 10th day, which was far higher than that of other experimental groups. This study provides a new strategy and experimental basis for the applications of functional hydrogels in wound repair.