An assay method to determine a concentration of an analyte in a sample, said method comprising: providing a conductive metallic material on a substrate, wherein the metallic material is shaped as metallic particles, nanostructures, islands or colloids, wherein the metallic particles, nanostructures, islands or colloids are separated from about 10 to 50 nm apart, wherein at least a portion of the metallic material is in contact with a polar solvent and wherein the substrate has a first end and an opposing second end; connecting the first and second end of the substrate and at least some of the metallic particles, nanostructures, islands or colloids positioned thereon to a first and second electrode, wherein the first and second electrodes are connected to a current reading device; introducing at least one intrinsic or extrinsic fluorophore for disposing near the metallic material, wherein the intrinsic or extrinsic fluorophore is capable of interacting or reacting with the analyte to provide one or more optical signals, and wherein excitation of the intrinsic or extrinsic fluorophore by electromagnetic energy induces a mirror dipole in the metallic material and such mirror dipole in the metallic material is enhanced by a predetermined proximity to the intrinsic or extrinsic fluorophore; applying electromagnetic energy from an electromagnetic energy source to excite the intrinsic or extrinsic fluorophore and inducing a mirror dipole in the metallic material causing electrical current flow; and measuring the electrical current flow by a current flow detector, wherein the concentration of analyte in the sample is determined from the induced electrical current in the metallic material. providing a conductive metallic material on a substrate, wherein the metallic material is shaped as metallic particles, nanostructures, islands or colloids, wherein the metallic particles, nanostructures, islands or colloids are separated from about 10 to 50 nm apart, wherein at least a portion of the metallic material is in contact with a polar solvent and wherein the substrate has a first end and an opposing second end; connecting the first and second end of the substrate and at least some of the metallic particles, nanostructures, islands or colloids positioned thereon to a first and second electrode, wherein the first and second electrodes are connected to a current reading device; introducing at least one intrinsic or extrinsic fluorophore for disposing near the metallic material, wherein the intrinsic or extrinsic fluorophore is capable of interacting or reacting with the analyte to provide one or more optical signals, and wherein excitation of the intrinsic or extrinsic fluorophore by electromagnetic energy induces a mirror dipole in the metallic material and such mirror dipole in the metallic material is enhanced by a predetermined proximity to the intrinsic or extrinsic fluorophore; applying electromagnetic energy from an electromagnetic energy source to excite the intrinsic or extrinsic fluorophore and inducing a mirror dipole in the metallic material causing electrical current flow; and measuring the electrical current flow by a current flow detector, wherein the concentration of analyte in the sample is determined from the induced electrical current in the metallic material.