Glucose biosensors: progress, current focus and future outlook

Glucose serves as the primary source of energy to cells in our physiological system, enabling them to perform important functions including: nerve cell conduction, muscle cell contraction, active transport and production of chemical substances. Lower blood glucose concentration can cause seizure, loss of consciousness and irreversible cell damage. While excessive blood glucose concentration has a detrimental effect (glucotoxicity) potentially causing blindness, renal failure, cardiac and peripheral vascular disease, and neuropathy. Thus, simultaneous detection of intracellular and extracellular glucose is critically important from the view point of diagnosis and to understand the relationship between intracellular glucose and the metabolic control systems within the cells. The focus of development of third generation of biosensors is driven by nanotechnology. In this regard, carbon dots are promising building blocks for biosensors because of their unique optical properties and biocompatibility. They can be chemically modified to facilitate detection of biologically relevant molecules with high sensitivity and selectivity. We describe here our preliminary studies dealing with the synthesis, characterisation and intracellular response of glucose to carbon dots and discuss their potential as effective biosensors. Also discussed are the basic principles underlying the detection of glucose and the progress made in the development of biosensors for glucose detection.