Silicon chip based devices were fabricated as described by Dawson et al, with the subsequent modifications proposed by Seymour et al 71 also included. Each sensor consisted of two combs of gold interdigitated ultramicroelectrodes, as working electrodes, as well as platinum pseudo reference and gold counter electrodes. Chips were designed with a peripheral microSD pinout to permit interfacing with external electronics via a microSD port. All devices were fabricated on 4-inch silicon wafers bearing a thermally grown 300 nm silicon dioxide layer. Blanket metal evaporation of Titanium (10 nm) and Gold (100 nm) (Temescal FC-2000 E-beam evaporator) and lift off technique to yield interdigitated microband comb structures. The first comb (WE1) had 33 tines, while the second comb two (WE2) had 34 tines. Each comb was 1 µm wide, 178 µm long, 100 nm high and had an inter-electrode gap of 2 µm. A second metal evaporation and subsequent lift-off step was undertaken to pattern the interconnection tracks, contact pads and the gold counter electrode (90 µm x 7mm). A third and final metal evaporation was performed to pattern the platinum pseudo reference electrode (90 µm x 7mm).