Renewable Nanostructured Interfaces for Bioelectronic Applications
B.L. Hassler, N. Kohli, I. Lee and R.M. Worden
Michigan State University, US
bioelectronic regenerate, revesible, dehydrogenase, toluidine blue, nicotinamide adenine dinucleotide, NAD, biosensor, renewable, polyelectrolyte
Bioelectronic interfaces that establish electrical communication between redox enzymes and electrodes have potential applications as biosensors, biocatalytic reactors, and biological fuel cells. However, these interfaces contain labile components, such as enzymes and cofactors, which must be replaced periodically to allow long-term use. To address this need, we have developed a renewable bioelectronic interface platform that allows the enzyme and cofactor to be easily removed and replaced. These components are covalently bound to a positively charged polyelectrolyte (e.g., polyethyleneimine, PEI), which adsorbs onto the carboxylic-functionalized electrode via ionic interactions. Reducing the pH causes protonation of the carboxylic acid groups, decreasing the electrostatic interactions and releasing the PEI from the surface. After neutralization, the bioelectronic interface can be reconstituted. The approach was demonstrated using a thermophilic enzyme (secondary alcohol dehydrogenase of Thermoanaerobacter ethanolicus) and its cofactor ( -nicotinamide dinucleotide phosphate). Cyclic voltammetry, chronoamperometry, constant potential amperometry, electrochemical impedance spectroscopy, and Fourier transform infrared spectroscopy were used confirm formation, removal, and reconstitution of the bioelectronic interface. The regenerated interface exhibited a similar surface coverage, electron transfer coefficient, and turnover rate as the original layer.
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Nanotech 2007 Conference Program Abstract