Interdigitated array and method of manufacture

A method of making a sensor card, comprising the steps of:

• applying a first conductive ink to a substrate in a first pattern to form a first conducting element and a second conducting element, the first and second conducting elements having first and second widths, the first conductive ink having a particle size of greater than 5 microns;
• applying a second conductive ink to the substrate with an aerosol jetting apparatus in a second pattern to form first fingers interleaved with second fingers, the first and second fingers having third and fourth widths that are less than the first and second widths of the first and second conducting element, the first fingers being spaced a distance from the second fingers between 10 nanometers and 1 millimeter, the second conductive ink having a particle size of less than or equal to 5 microns,
• wherein the first conducting element and the first fingers are electrically connected to form a first electrode of a sensor unit, and the second conducting element are electrically connected to the second fingers to form a second electrode of the sensor unit;
• and
• wherein the step of applying the first conductive ink to the substrate is defined further as applying the first conductive ink to the substrate utilizing a non-aerosol jetting apparatus selected from a group consisting of a screen printing apparatus, a stenciling apparatus, an electro-deposition apparatus, a sputtering apparatus, a jetting apparatus, a laser ablation apparatus and combinations thereof;
• and
• further comprising the step of applying sensor-immobilized biomolecule receptors on the substrate between the first electrode and the second electrode such that the first electrode is electrically connected to the second electrode upon one or more of the biomolecule receptors binding to a biomolecule.