Carbon nanotubes (CNTs) have been incorporated in electrochemical
sensors to decrease overpotential and improve sensitivity. In this
review, we focus on recent literature that describes how CNT-based
electrochemical sensors are being developed to detect neurotransmitters,
proteins, small molecules such as glucose, and DNA. Different types of
electrochemical methods are used in these sensors including direct
electrochemical detection with amperometry or voltammetry, indirect
detection of an oxidation product using enzyme sensors, and detection of
conductivity changes using CNT-field effect transistors (FETs). Future
challenges for the field include miniaturizing sensors, developing
methods to use only a specific nanotube allotrope, and simplifying
manufacturing.Carbon nanotubes have aroused great interest since their discovery in 1991. Because of the vast potential of these materials, researchers from diverse disciplines have come together to further develop our understanding of the fundamental properties governing their electronic structure and susceptibility towards chemical reaction. Carbon nanotubes show extreme sensitivity towards changes in their local chemical environment that stems from the susceptibility of their electronic structure to interacting molecules. This chemical sensitivity has made them ideal candidates for incorporation into the design of chemical sensors. Towards this end, carbon nanotubes have made impressive strides in sensitivity and chemical selectivity to a diverse array of chemical species. Despite the lengthy list of accomplishments, several key challenges must be addressed before carbon nanotubes are capable of competing with state-of-the-art solid-state sensor materials. The development of carbon nanotube based sensors is still in its infancy, but continued progress may lead to their integration into commercially viable sensors of unrivalled sensitivity and vanishingly small dimensions.
