Biomimetic interfaces for a multifunctional biosensor array microsystem

Bioelectronic interfaces that allow dehydrogenase enzymes to electrically communicate with electrodes have potential applications in the development of biosensors and biocatalytic reactors. A fully scalable, post-CMOS-compatible, three-electrode interface to biochemical sensors, consisting of Ti/Au working and auxiliary electrodes and a Ti/Au/Ag/AgCl reference electrode, has been developed. Also described is a tri-functional linking molecule that binds the mediator and cofactor to the electrode in a unique spatial arrangement in which the dehydrogenase enzyme can bind to cofactor and multistep electron transfer between the electrode and enzyme is achieved. This approach provides greater flexibility in assembling complex bioelectronic interfaces than is possible with previously reported, linear linking molecules. A cysteine molecule was self-assembled on a gold electrode via a thiol bond. The electron mediator toluidine blue O (TBO) and the cofactor, β-nicotinamide adenine dinucleotide phosphate (NADP⁺) were chemically attached to cysteine via the formation of amide bonds. Cyclic voltammetry, was used to demonstrate the electrical activity, and enzymatic activity of the resulting bioelectronic interface.