Electrochemically addressable functionalization and parallel readout of a DNA biosensor array

We introduce an electrochemical method for the directed in situ assembly of various specific oligonucleotide capture probes onto different sensing elements of a multielectrode array in the aqueous environment of a flow cell. Surface plasmon microscopy is utilized for the on-line recording of the various functionalization steps. Hybridization reactions between targets from solution to the different surface-bound complementary probes are monitored by surface plasmon field-enhanced fluorescence microscopy using targets that are either labeled with organic dyes or with semiconducting quantum dots for color-multiplexing. This study provides a new approach for the fabrication of (small) DNA arrays and the recording and quantitative evaluation of parallel hybridization reactions.