Carbon nanotubes direct electron transfer

Keywords bio-application, biocompatability, biosensor, carbon nanotube, direct electron transfer, electroconductivity, enzyme, functionalization, immobilization, quantum dot... 

Figure 17.4 Cartoon representation of strategies for studying and exploiting enzymes on electrodes that have been used in electrocatalysis for fuel cells, (a) Attachment or physisorption of an enzyme on an electrode such that redox centers in the protein are in direct electronic contact with the surface, (b) Specific attachment of an enzyme to an electrode modified with a substrate, cofactor, or analog that contacts the protein close to a redox center. Examples include attachment of the modifier via a conductive linker, (c) Entrapment of an enzyme within a polymer containing redox mediator molecules that transfer electrons to/from centers in the protein, (d) Attachment of an enzyme onto carbon nanotubes prepared on an electrode, giving a large surface area conducting network with direct electron transfer to each enzyme molecule.

Recently, direct electron transfer to microperoxidases adsorbed on carbon nanotube-modified platinum electrodes has been observed [24], The redox potential for this direct electron transfer is-0.4 V vs SCE, the same as that for the microper-... 

Direct electron transfer of proteins and enzymes on carbon nanotube electrodes... 

C. Cai and J. Chen, Direct electron transfer of glucose oxidase promoted by carbon nanotubes. Anal. Biochem. 332, 75-83 (2004). 

Y.D. Zhao, W.D. Zhang, H. Chen, and Q.M. Luo, Direct electron transfer of glucose oxidase molecules adsorbed onto carbon nanotube powder microelectrode. Anal. Sci. 18, 939-941 (2002). 

A. Guiseppi-Elie, C.H. Lei, and R.H. Baughman, Direct electron transfer of glucose oxidase on carbon nanotubes. Nanotechnology 13, 559-564 (2002). 

Y. Liu, M.K. Wang, F. Zhao, Z.A. Xu, and S.J. Dong, The direct electron transfer of glucose oxidase and glucose biosensor based on carbon nanotubes/chitosan matrix, Biosens. Bioelectron. 21, 984-988... 

J.Z. Xu, J.J. Zhu, Q. Wu, Z. Hu and H.Y. Chen, Direct electron transfer between glucose oxidase and multi-walled carbon nanotubes, Chin. J. Chem., 21 (2003) 1088-1091. 

Gao RF, Zheng JB (2009) Amine-terminated ionic liquid functionalized carbon nanotube-gold nanoparticles for investigating the direct electron transfer of glucose oxidase. Electrochem Commun 11 608-611... 

Carbon nanotubes (CNTs), as a new class of nanomaterial, were discovered in 1991 by Iijima [55] and have also been employed in biosensors. Such an application is attributed to their unique electrical properties, which make a redox active close to the surface of proteins, and enable direct electron transfer between proteins and electrode [56]. CNTs are highly conductive (rapid electron transfer) nanomaterials with great promise for applications in biochemical sensing [57-59], Several successful sensors based on CNTs have been reported for the detection of substances, including for NADH [58], glucose [59], cytochrome c [60] and thymine [61]. 

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