Carbon quantum dots: promising carbon nanomaterials for organic nanozymes, biological imaging and therapeutic applications

Carbon dots, the organic analogs of quantum dots represent the class of fluorescent nanoparticles derived from carbon sources, which are emerging non-toxic biological imaging agents, carbon-based nanozymes and therapeutic agents. These nanostructured carbon dot materials consist of either graphitic or an amorphous carbon core that is covered by varying functional groups, together making these particles chemically stable, water-dispersible, bio-compatible, photoluminescent and photostable. This chapter begins with a detailed description of these nanostructured carbon materials, their classification based on structure and composition, the origin of their fluorescence, synthetic strategies, and surface modification using various chemical functional groups. This is followed by their application as bio-imaging agents, carbon dots-based nanozymes as well as their therapeutic potential and how strongly they rely upon doping, surface modification, biocompatibility, and the less immunogenic response within the biological system.