Multifunctional carbon quantum dots decorated self-healing hydrogel for highly effective treatment of superbug infected wounds

Rapid healing of wounds infected by bacteria, especially multidrug-resistant bacteria, is a common clinical challenge. Local bacterial infection causes excessive reactive oxygen species (ROS) that further induce oxidative stress and inflammatory responses, which impairs cell migration, angiogenesis and delays cutaneous regenera-tion. Herein, we designed a novel type of carbon quantum dots (CQDs) derived from herbal medicines. The CQDs are able to against gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA), and possessed SOD-like as well as CAT-like activities for scavenging ROS. The biocompatible CQDs could protect HUVECs migration and angiogenesis from oxidative stress damage. Moreover, the expression of NO and pro -inflammatory cytokines (TNF-alpha and IL-6) of LPS-induced macrophages could be downregulated by the CQDs. Besides, the self-healing hydrogel decorated with multifunctional CQDs were prepared via the reaction between OSA and CMCS through Schiff base linkage for better wound management. The CQDs/hydrogel could contin-uously eliminate bacteria and scavenge ROS to modulate the complex oxidative stress microenvironment. The results of animal experiments demonstrated that the CQDs/hydrogel exerted the effects of eliminating MRSA, anti-inflammation, and promoting angiogenesis, which was manifested in enhancing wound healing, epithelial regeneration and collagen disposition. Therefore, the CQDs/hydrogel is excellent candidate for MRSA-infected skin wound healing.