Naturally Derived Carbon Dots as Bioimaging Agents

Abstract

The recent advances in nanoscience and technology have opened new avenues for carbon-based nanomaterials. Especially, Carbon dots (CDs) have gained significant attention due to their simple, economic and rapid green synthesis. These materials exhibit excellent water solubility, fluorescence emission, high fluorescence quantum yield, Ultraviolet (UV) to Infrared (IR) range absorbance and high bio-compatibility. Therefore, these materials are widely used for various biological applications including bio-imaging. With the integration and doping of surface passive agents and elements, respectively influenced the enhancement of fluorescence property of CDs. Also, the conjugation of receptor-based targeting ligands leads to targeted bioimaging. CDs in combination with other imaging contrast agents lead to the development of novel contrast agents for bimodal imaging and multimodal imaging techniques. The combination of diagnostic CDs with therapeutic agents resulted in the formation of theragnostic CDs for image guided therapies. In this chapter, a comprehensive view on the top-down and bottom–up green synthesis methods for naturally derived CDs discussed. Further, unique physical, chemical, optical and biological properties of CDs described. Finally, fluorescence based bimodal and multimodal imaging techniques also described.