Studies On Glucose Electrochemical Biosensor Based On Carbon Nanotubes And Platinum Nanoparticles

Electrochemical biosensors are effective tools for detecting glucose level, to develop new materials for electrode surface modification and to enhance electrodes'sensitivity and lifetime became an important study area. Nanomaterials are used to enhance electrodes'sensitivity due to their special electrical properties; Carbon nanotubes and novel metal nanoparticles, including platinum, gold, silver, are well-used among all kinds of nanomateirals. Therefore, this research focuses on the details as follow:(1) A fast, simple in situ chemical reductive method is reported which can mass-produce nanomaterials onto electrodes'surfaces, and this method was successfully applied to modify platinum nanoparticles onto glass slides. Gold nanoparticles with diameter around 10nm were sputtered onto a glass slide as seeds, and then the glass slide was immersed into H2PtCl4 solution to produce Pt nanoparticle layer, and finally glucose oxidase was electrodeposited onto the outmost layer. The biosensor fabricated by this method illustrated outstanding features.(2) A seed-mediated method was reported to grow nanoparticles onto glass carbon electrode. 3.5nm gold nanoparticles and carbon nanotubes were deposited onto electrode's surface, and then the electrode was immersed into H2PtCl4 solution to produce Pt nanoparticles layer by reduction. Glucose oxidase was electrodeposited onto electrode's surface to fabricate the glucose oxidase-based electrochemical biosensor. The sensor produced by this method showed excellent properties, including high sensitivity (4.49μA mM-1), fast response time (2s), low detection limit (0.5μM) and wide linear range (1μM– 4mM). This method can be used to fabricate many oxidase-based electrodes, and has wide application potential.(3) A novel amperometric glucose sensor is reported, using ferrocene -functionalized carbon nanotubes to modify the electrodes. First amidation the carbon nanotubes, and then use 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) to covalent bind the carboxyl group of ferrocene to the amino group of carbon nanotubes, and finally use bovine serum albumin (BSA) covalent binding method to immobilize the glucose oxidase onto the electrode to fabricate the sensor. Cyclic voltammograms and current-time methods were carried out to characterize the electroactivity of the proposed electrode. The results show that the response of proposed electrode toward peroxide hydrogen is higher than those of electrodes modified by simply carbon nanotubes and ferrocene respectively.