Systems and devices for photoelectrophoretic transport and hybridization of oligonucleotides

Abstract

A platform for photoelectrophoretic transport and electronic hybridization of fluorescence labeled DNA oligonucleotides in a low conductivity electrolyte is described. A chemically stabilized semiconductor photodiode or photoconductor surface is coated with a streptavidin-agarose permeation layer. Micro-illumination of the surface generates photo-electrochemical currents that are used to electrophoretically transport and attach capture strands, preferably biotinylated DNA, to arbitrarily selected locations. The same process is then used to transport and electronically hybridize fluorescence labeled DNA target strands to the previously attached capture strands. Signal detection is accomplished either by a fluorescence scanner or a CCD camera. This represents a flexible electronic DNA assay platform that need not rely on pre-patterned microelectronic arrays.

We claim:  
     
         1 . A device for effecting the photoelectric transport of charged materials in a liquid environment, comprising: 
 a substrate having a first face and a second face, the substrate capable of generating a photocurrent;    a conductor contacting at least a portion of the first face of the substrate;    a permeation layer supported on the second face;    attachment entities coupled to the permeation layer;    a liquid in contact with the permeation layer;    an electrode in contact with the liquid; and    a light source disposed to illuminate at least a portion of the substrate, thereby to induce a current within the device.    
     
     
         2 . The device of  claim 1 , wherein the substrate is adapted to generate a photo-current.  
     
     
         3 . The device of  claim 1 , wherein the substrate is adapted to generate a photo electrochemical current.  
     
     
         4 . The device of  claim 1 , wherein the substrate is a semiconductor.  
     
     
         5 . The device of  claim 4 , wherein the semiconductor is an n-type semiconductor.  
     
     
         6 . The device of  claim 4 , wherein the semiconductor is silicon.  
     
     
         7 . The device of  claim 1 , wherein the conductor contacting at least a portion of the first face of the substrate is a film.  
     
     
         8 . The device of  claim 7 , wherein the film is a copper film.  
     
     
         9 . The device of  claim 1 , further comprising a chemical layer supported on the substrate.  
     
     
         10 . The device of  claim 9 , wherein the chemical layer includes Mn 2 O 3 .  
     
     
         11 . The device of  claim 10 , further comprising a metal layer disposed between the substrate and the chemical layer.  
     
     
         12 . The device of  claim 11 , wherein the metal layer disposed between the substrate and the chemical layer is palladium.  
     
     
         13 . The device of  claim 1 , comprising a containment structure disposed in fixed relation with the substrate.  
     
     
         14 . The device of  claim 13 , wherein the containment structure includes a sheet-like containment system having an aperture through the sheet.  
     
     
         15 . The device of  claim 14 , wherein the sheet is a Teflon sheet.  
     
     
         16 . The device of  claim 1 , wherein the electrode is a ring electrode.  
     
     
         17 . The device of  claim 1 , further comprising a reference electrode adapted to contact the liquid environment in contact with the device.  
     
     
         18 . The device of  claim 1 , further comprising an optical fiber disposed between the light source and the device.  
     
     
         19 . The device of  claim 18 , wherein the optical fiber is a single mode optical fiber.  
     
     
         20 . The device of  claim 1 , wherein the light source includes a laser.