Electrochemical biosensing platforms using poly-cyclodextrin and carbon nanotube composite

Carbon nanotubes (CNTs) were "dissolved" in mixed solution of cyclodextrin (CD) and cyclodextrin prepolymer (pre-CDP) and were used as modifier to fabricate chemical modified electrode The dispersions of CNTs in different solutions were characterized using UV-vis spectrophotometer The insoluble conducting composite film of poly-cyclodextin (CDP) and carbon nanotube was synthesized, and glucose oxidase (GOx) was immobilized on the film to fabricate amperometric biosensor. The CNT-CDP electrode was stable It can keep the exceptional chemical and physical properties of CNTs and the host-guest chemical reaction ability of cyclodextrins Cyclic voltammetry measurements of potassium ferricyanide solution (50 mM, and scan rate 100 mV S-1) shows that the CDP film was compact and the CNT-CDP film maintains the electrocatalytic activity of CNT. Glucose oxidase was used as a model enzyme to prepare a glucose biosensor. The bioactivity of immobilized glucose oxidase was maintained due to the biocompatibility of cyclodextrin Amperometric measurements were done with different concentrations of glucose The CNT-CDP/GCE-GOx biosensor has wide concentration ranges and good sensitivity to glucose It showed a detection limit of 3.5 mu M with a linear range from 0 004 to 3 23 mM and from 426 to 10 00 mM In addition, the biosensor can be operated under wide pH range (pH 5 6-7.8) without great changes in its sensitivity (C) 2010 Elsevier B V All rights reserved