Electrode for dielectrophoretic apparatus, dielectrophoretic apparatus, method for manufacturing the same, and method for separating substances using the electrode or dielectrophoretic apparatus

Abstract

To provide an electrode for a dielectrophoretic apparatus in which a background detected by reflecting an excited light on an electrode present under the substance (molecule) is reduced and an S/N ratio is enhanced. Also, there is provided an dielectrophoretic apparatus, in an apparatus in which a liquid containing substances to be separated is present in a non-uniform electric field formed by a dielectrophoretic electrode, and separation is carried out by a dielectrophoretic force exerting on the substances, wherein the collecting ability of substances is enhanced. The present invention is characterized in that a vacant space is provided in an electrode whereby substances subjected to influence by a negative dielectrophoretic force can be concentrated in said vacant space of an electrode, or above or below portion of the space.

1 - 5 . (canceled) 
     
     
         6 . A method for separating substances in a liquid, comprising the steps of:
 providing two or more dielectrophoretic electrodes, wherein the dielectrophoretic electrodes are at an electrode level on a substrate and the places among the electrodes on the substrate are at lower levels than the electrode level, so as to generate a non-uniform electric field,   subjecting the liquid containing the substances to be separated in the non-uniform electric field generated by applying voltage to the dielectrophoretic electrodes, and   separating the substances by utilizing difference in the dielectrophoretic forces exerting on said substances.   
     
     
         7 . The method of  claim 6 , wherein:
 the step of subjecting the liquid containing substances to be separated in the non-uniform electric field comprises causing the liquid to flow into the non-uniform electric field generated by the dielectrophoretic electrodes, and separation is carried out by an interaction of the dielectrophoretic force exerting on said substance and fluid drag.   
     
     
         8 . The method according to  claim 7  wherein said dielectrophoretic electrodes are held by a convex construction on said substrate to make the places among said dielectrophoretic electrodes at lower levels than said electrode level. 
     
     
         9 . The method according to  claim 6 , wherein the places among said electrodes at lower levels than said electrode level are formed by excavating the substrate with physical or chemical means. 
     
     
         10 . The method according to  claim 9 , wherein the places among said electrodes at lower levels than said electrode level are formed by excavating the substrate with a chemical means, and wherein said chemical means is an etching using an etching liquid for the substrate.