Study On The Fabrication And Application Of Electrochemical Biosensor Based On Carbon Nanotubes

Since their discovery by Iigima in 1991, carbon nanobutes (CNTs) have been received considerable attention in many aspects because of their extraordinary structure, unique mechanical and electrical properties. CNTs can promote electron transfer and lower potential of some electroactive chemicals. Their biocompatibility and large surface area make CNTs ideal candidates for constructing high-performance biosensors. This paper concentrated on the combination of CNTs with biomoleculars to fabricate biosensors. Hemoglobin, glucose oxidase and laccase were immobilized on the surface of CNTs and relevant biosensors were prepared. The details are summarized as follows:1. Hemoglobin was immobilized on long CNT/chitosan and short CNT/chitosan composite modified electrode, and the direct electron transfer and catalytic property were comparatively studied. Short CNTs were obtained by ball milling. CNTs and CNTs/chitosan composites were characterized by TEM and SEM. Cyclic voltammetry, amperometric i-t cruve and impedance method were used to comparatively study the direct chemistry and catalytic property of Hemoglobin towards H2O2 on the two kinds of composites.2.Mediator ABTS was absorbed on the surface of CNTs, and a laccase biosensor was developed using chitosan as fixative. The electrochemical behavior of ABTS on multi-walled carbon nanotubes was studied carefully. The direct electron transfer of laccase was realized, and the biosensor was sensitive to oxygen. We optimized several experiment parameters such as the modified amount of ABTS-MWCNTs solution, pH and temperature for the best performance of the laccase biosensor.