Electrochemical Study of Chitosan‐SiO2‐MWNT Composite Electrodes for the Fabrication of Cholesterol Biosensors |
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| Authors: | Ashutosh Tiwari Shaoqin Gong |
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| Affiliation: | 1. Department of Mechanical Engineering, University of Wisconsin‐Milwaukee, 3200 North Cramer Street, Milwaukee, WI 53202, USA;2. Department of Materials, University of Wisconsin‐Milwaukee, 3200 North Cramer Street, Milwaukee, WI 53202, USA |
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| Abstract: | We report a novel composite electrode made of chitosan‐SiO2‐multiwall carbon nanotube (CHIT‐SiO2‐MWNT) composite coated on the indium‐tin oxide (ITO) glass substrate. Cholesterol oxidase (ChOx) was covalently immobilized on the CHIT‐SiO2‐MWNT/ITO electrode that resulted in a ChOx/CHIT‐SiO2‐MWNT/ITO cholesterolactive bioelectrode. The CHIT‐SiO2‐MWNT/ITO and ChOx/CHIT‐SiO2‐MWNT/ITO electrodes were characterized with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The influence of various parameters was investigated, including the applied potential, pH of the medium, and the concentration of the enzyme on the performance of the biosensor. The cholesterol bioelectrode exhibited a sensitivity of 3.4 nA/ mgdL?1 with a response time of five seconds. The biosensor using ChOx/CHIT‐SiO2‐MWNT/ITO as the working electrode retained its original response after being stored for six months. The biosensor using ChOx/CHIT‐SiO2‐MWNT/ITO as the working electrode showed a linear current response to the cholesterol concentration in the range of 50–650 mg/dL. |
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| Keywords: | Cholesterol biosensor Electrochemical study Multiwall carbon nanotubes Cholesterol oxidase Chitosan |
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