278096 SAM-Modified Microdisc Electrode Arrays (MDEAs) with Functionalized Carbon Nanotubes for Amperometric Biosensors

Tuesday, October 30, 2012: 10:45 AM
Pennsylvania East (Westin )
Anthony Guiseppi-Elie, Center for Bioelectronics, Biosensors and Biochips, Clemson University, Anderson, SC

A novel biosensor for glucose, one that makes use of covalent conjugation of glucose oxidase (GOx) to acid-chopped, chemically modified single-walled carbon nanotubes (SWNT) that were themselves covalently immobilized via alkane thiol SAMs onto gold microdisc electrode arrays (MDEAs) has been constructed and evaluated. Amperometric biotransducers fabricated by chemisorbing self-assembled monolayers (SAM) of cysteamine (CA) and 11-amino-1-undecanethiol (11-AUT) onto 100 mm diameter gold microdisc arrays, resulting in MDEA-Au|CA|SWNT-COOH and MDEA-Au|11-AUT|SWNT-COOH electrodes, were characterized electrochemically using cyclic voltammetry and amperometry in the presence of ferrocene. Subsequent covalent conjugation of GOx to free -COOH groups using EDC NHS hetero bifunctional coupling, produced MDEA-Au|CA|SWNT-CONH-GOx and MDEA-Au|11-AUT|SWNT-CONH-GOx electrodes that were similarly characterized in changing concentrations of glucose. The combination of SWNT at the CA-modified MDEA surface compared to the other electrode surfaces gave a well-resolved voltammogram with highest peak currents (Ipa = 5.54 x 10-4 A, Ipc = 2.34 x 10-4 A at 100 mV/s). The resulting amperometric glucose biosensor displayed linear responses between 0.5 and 3.0 mM glucose with a response time of 40s and was superior to constructs using 11-AUT.

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