The present invention relates to a method of manufacturing a detection device which involves providing a substrate having a layer of electrically conductive material and a first layer of photosensitive material. Next, the substrate is subjected to a first level photolithography treatment to produce an electrical conductor containing conductive fingers with spaces between them. Finally, biological probes are attached to the conductive fingers under conditions effective to form a gap between the biological probes on the spaced apart conductive fingers, whereby a target molecule, if present in a sample, can bind to a pair of the biological probes on the spaced apart conductive fingers to bridge the gap between the biological probes, allowing detection of the target molecule.