Using the proposed fabrication method, the 3×3 mm working areas of two ITO microchips were successfully and correctly overlapped using a double-sided tape and a microchannel was formed for test solution delivery. In other words, the fabrication of a dual ITO microchip was realized using a simple fabrication procedure without using laborious and precise alignment processes. The electrochemical behavior of a single ITO was analyzed by CV using 0.1 mM FcCH2OH and 200 µM DA, as shown in Figure . The CV curves as expected confirmed the electrochemical detection of FcCH2OH and DA. As can be seen in the Nyquist plot of ITO, the Rct value was measured to be 590 Ω (Figure ). In dual-mode chronoamperometry, redox-cycling capacity of a dual ITO microchip was studied by first setting the potential of both the generator and collector electrodes first at +0.35V (vs. Ag/AgCl) and then +0.35 and 0 V (vs. Ag/AgCl), respectively (Figure ). When the two electrodes were set at +0.35V (vs. Ag/AgCl), both electrodes oxidize and consume FcCH2OH in the microchannel, resulting a low current (0.08 µA). However, when the generator and collectors were set at +0.35 and 0 V (vs. Ag/AgCl), respectively, the generator electrode oxidizes FcCH2OH to FcCH2OH + which is then reduced back to FcCH2OH by the collector electrode. Thus, a redox-cycling is induced, resulting a much higher current (3.1 μA). Figure shows the behavior of dual-mode CV curves at different scanning rates in 0.1 mM FcCH2OH. The performance of the dual ITO microchip for the detection of DA was evaluated in dual mode. Basically, the potentials of generator and collector electrodes were set at +0.35 and 0 V (vs. Ag/AgCl), respectively, as described above. As the DA is oxidized to DA quinone (DAQ) by the generator electrode, DAQ then diffuses to the collector electrode surface where it is reduced back to DA, resulting signal amplification and a higher current. Figure ai-bi show the oxidation and reduction-based choronoamperometric responses obtained in DA solutions at varying concentrations, respectively. In both cases, the currents at 120s were used to obtain calibration curves (Figure aii-bii). The both calibration curves had an R 2 value greater than 0.99. The LOD values for the generator and collector electrodes were calculated to be 0.15 and 1.46 μM, respectively. The microchip requires less than 1 µl of solution for analysis and can be applied for immunosensing with enzymes producing molecules that can be electrochemically cycled between two electrodes.