Structural and characteristic analysis of carbon nanotubes-ionic liquid gel biosensor

The structure and characteristic of carbon nanotubes-ionic liquid gel biosensor were studied by voltammetry, microscopy and spectroscopy. Various biomolecules were electrochemically detected with this gel biosensor such as glucose oxidase and NADH. The excellent electrochemical behavior of this gel biosensor might be due to the following three main factors: (1) the inherently perfect electrochemical characteristic of multi-wall carbon nanotubes (MWNTs); (2) the better solvent effect and conductivity of ionic liquid as well as the proper interactions between MWNTs and ionic liquid; (3) the proper mixing ratio of MWNTs to ionic liquid. Meanwhile, the interactions between MWNTs and ionic liquid were carefully studied as well. It can be concluded that the non-covalent (pi-pi) interaction between the imidazole loop of ionic liquid and MWNTs side wall should play an important role. This work gives a further understanding of what results in the high sensitivity and selectivity of such a biosensor to some biomolecules, and provides a simple and easy approach to design new biosensors with various nano-particles and versatile ionic liquid. (C) 2007 Elsevier B.V. All rights reserved.