Carbon nanomaterials and their composites for electrochemical glucose biosensors: A review on fabrication and sensing properties

With the increasing prevalence of diabetes that increases the risk of cardiovascular diseases, kidney failure, nerve degeneration, eye damage, lower extremity amputations and birth defects, the demand for highly efficient glucose sensors has attracted significant attention worldwide. In this regard, carbon nanomaterials-based electrochemical glucose sensors have shown great potential in the detection and monitoring of glucose. Different forms of carbon such as carbon nanotubes, graphene, reduced graphene oxide, carbon nanofibers, activated and amorphous carbon, carbon spheres, carbon nanoparticles, carbon quantum dots, carbon nanorods, carbon nanocages etc. and their hybrids have been extensively researched for highly efficient glucose sensors due to their large surface area, porosity, lightweight, thermal stability, excellent mechanical properties, ease of fabrication, high electrical conductivity, excellent catalytic properties and fast electron transfer kinetics. Due to their large surface area and tunable porosity, carbon nanomaterials have been used as a scaffold for the immobilization of large quantities of bioreceptor units such as enzymes and highly catalytic metal or metal oxide nanostructures, which can enhance the electroanalytical properties of the biosensor. In this review paper, the fabrication and electroanalytical properties of carbon nanomaterials based enzymatic and nonenzymatic electrochemical glucose sensors have been reviewed and their sensing mechanisms are discussed.