Photoelectrophoretic transport and hybridization of DNA oligonucleotides on unpatterned silicon substrates

We describe a platform for photoelectrophoretic transport and electronic hy bridization of fluorescence-labeled DNA oligonucleotides in a low conductiv ity electrolyte. At the core of the platform is a chemically stabilized sem iconductor photodiode or photoconductor surface coated with a streptavidin- agarose permeation layer. Micro-illumination of this surface generates phot oelectrochemical currents that are used to electrophoretically transport an d attach biotinylated DNA capture strands to arbitrarily selected locations . The same process is then used to transport and electronically hybridize f luorescence-labeled DNA target strands to the previously attached capture s trands. Signal detection is accomplished either by a fluorescence scanner o ra CCD camera. This represents a flexible electronic DNA assay platform tha t does not rely on pre-patterned microelectronic arrays.