Electrochemical Sensing and Biosensing-Based on Carbon Nanodots

Carbon quantum dots (CQDs) or simply carbon nanodots (CNDs) represent emerging materials in the form of nanocarbon, which have been advocated for diversified applications. Different top-down and bottom-up procedures are applicable to synthesize inexpensive 2-D nanomaterials. Based on their superconductivity and rapid electron transfer, CNDs with diameters below 10 nm form nanocomposites with metal nanoparticles, carbon graphene/nanotubes, and conducting polymers with enhanced catalytic activity and electrical conductivity. The surface of CNDs with abundant reactive groups facilitates bioconjugation with recognition biomolecules or the preparation of complex catalysts with enhanced charge transfer. CNDs can be doped with N, S, or P, which acts as reactive catalytic sites for electrocatalysis. Such distinct features are attributed to the fabrication of reliable biosensing platforms to target important analytes encompassing simple biomolecules, metal ions, proteins, and macromolecules. This chapter also unravels technical issues and potential uses of CNDs in electroanalysis toward developing ideal devices with low cost, high detection sensitivity, and selectivity.