Carbon dots as potential antioxidants for the scavenging of multi-reactive oxygen and nitrogen species

Selenium (Se) and metal-doped carbon dots (CDs) based nanoenzymes have bright prospects as antioxidants; however, the high cost of Se and potential biotoxicity of metal elements hinder their widespread application. In this work, inspired by Chinese herbs with anti-inflammatory properties, SB-HHD-CDs were prepared using Scutellaria barbata (SB) and Herba Hedyotis diffusae (HHD) as precursors through a hydrothermal method. The SB-HHD-CDs with excellent thermal and pH stability could rapidly scavenge multiple reactive oxygen and nitrogen species (RONS), such as superoxide anion, hydroxyl radicals, 1,1-diphenyl-2-picryl-hydrazyl radicals and nitric oxide radicals, at low concentrations. To demonstrate, the as-prepared SB-HHD-CDs were used as cost-effective additives and integrated into a cigarette filter system to effectively remove more than 80% of RONS from cigarette burning. Our work provides a new strategy for the synthesis of novel Se- and metal-free doped CDs-based nanoenzymes with powerful antioxidant capacity.