AN AMPEROMETRIC GLUCOSE BIOSENSOR BASED ON THE IMMOBILIZATION OF GLUCOSE OXIDASE ON THE CARBON NANOTUBES MODIFIED GLASSY CARBON ELECTRODE

CNTs have unique mechanical and electronic properties, combined with chemical stability, and behave electrically as a metal or semiconductor, depending on their structure. For sensing applications, CNTs have many advantages such as small size with larger surface area, excellent electron transfer promoting ability when used as electrodes modifier in electrochemical reactions, and easy protein immobilization with retention of its activity for biosensors. CNTs play an important role in the performance of electrochemical biosensors, immunosensors. Various methods have been developed for the design of sensors using CNTs in recent years. In this work, we report the development of a highly sensitive and stable glucose sensor based on the effect of carbon nanotubes (CNTs). Since the isoelectric point (IEP) of glucose oxidase (GOx) is significantly different from that of CNTs nanoparticles, GOx was electrostatically bound to CNTs nanoparticles decorated onto a negatively charged MWNTs layer at the electrode surface .A Chitosan layer was further coated onto the GOx-contained CNTs nanoparticle layer to prevent the leakage of GOx. This unique multilayer structure (GOx/CNTs/CS/GC) provided a favorable microenvironment to maintain the bioactivity of GOx, which led to rapid amperometric response toward glucose. By loading different concentration of GOx at the sensor surface, we obtained a wide linear response range of 0.5 -15 mM for this sensor. This nanomaterialsbased glucose sensor was highly sensitive and showed favorable stability over a relatively longterm. KeywordsCarbon nanotubes, Biosensors, Glucose oxidase, Nanomaterials, Enzyme electrodes.