Electrochemical sensors based on CNTs

In this chapter, we will discuss electrochemical sensors based on CNTs. First, the properties and structures of CNTs, the preparation and purification of CNTs, and the advantages of electrochemical sensors based on CNTs are described, then, the fabrication of electrochemical sensors based on CNTs, applications of electrochemical sensors based on CNTs, and the spectroscopic characterization of CNT sensors are described. In conclusion, we will look into some aspects of the future direction for CNT sensors in clinical and biomedical research. 

In pharmaceutical fields, in Zhang Z. et al., 2010b, a novel sensitive and selective imprinted electrochemical sensor was constructed for the direct detection of L-histidine by combination of a molecular imprinting film and MWNTs. The sensor was fabricated onto an indium tin oxide electrode via stepwise modification of MWNTs and a thin film of MIPs via sol-gel technology. The introduced MWNTs exhibited noticeable enhancement on the sensitivity of the MIPs sensor, meanwhile, the molecularly impainted film displayed high sensitivity and excellent selectivity for the target molecule. H. Y. Lee Kim, 2009 reports of the synthesis of CNTs-MIP composite to be potentially applied to probe materials in biosensor system for theophylline recognition based on CNT field effect. Hydroxyl-... 

CNTs are also widely used in actuators [168-171], The addition of CNTs to PANI fibers increased the electromechanical actuation because the CNTs improved the mechanical, electronic and electrochemical properties of the PANI fibers [172-174], Composites based on CNTs are studied for a variety of sensor applications [175-177], For example, polypyrrole or PANI deposited on single-walled CNT networks that can be used as solid state pH sensors [178], A DNA sensor was created fi om a composite of polypyrrole and CNTs fimctionalized with carboxylic groups to covalently immobilize DNA onto CNTs [179], In general, the presence of CNTs tends to increase the overall and selectivity of biosensors, The thermal transport properties of polymer composites can be improved with the addition of CNTs due to the excellent thermal conductivity of CNTs, Such composite are quite attractive for usages as printed circuit boards, connectors, thermal interface materials, heat sinks, lids, housings, etc, [92,180],... 

A large number of papers on CNT-based sensors have been published in the last several years mainly because CNTs have the following advantages for the electrochemical... 

One interesting development in the carbon nanotube-based electrochemical sensor is the ability to self-assemble the CNT to other types of nano materials such as gold and silver nanoparticles or to a polymer surface. The enhancement of Raman signals of carbon nanotubes through the adsorption on gold or silver substrate has been also reported [142-146],... 

Research on the use of CNT-MPc based electrode in electroanalytical chemistry is still in its infancy. Without doubt, there is an enormous potential for using CNT-MPc-based electrodes for applications in areas such as environmental, industrial, food, pharmaceutical, clinical, and biomedical fields. Few studies have only been attempted with MPc complexes with Co, Fe and Ni as the central metals, meaning that there are many open doors for research on these and many other MPc complexes as redox mediators for the development of electrochemical sensors. Given the many advantages of electrochemical techniques (especially sensitivity to redox-active analytes, and amenability to automation,... 

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