Given these indices of performance, fluorescence detection and ECD on CombiMatrix 12K
microarrays are comparable; however, the instrumentation for ECD is considerably less complex and
far more rugged. The 12K ElectraSense microarray can be read in less than 15 seconds using a single 9
cm by 6 cm electronics board that is powered through a PC USB 2.0 port (Figure 5). This reduction in
size and complexity allows the array to be integrated into fluidic cartridges without concern for optical
paths and instrument stability. By modifications to the electronics board, a potentiostat can be
connected to individual electrodes or groups of electrodes for cyclic voltammetry and impedance
spectroscopy. Redox molecules, such as ferrocene, Methylene Blue and ferri/ferrocyanide can be used
for making these measurements on the ElectroSense microarray. Using a potentiostat to measure
molecular interactions on the array reduces the capacity of the microarray to multiplex; however, this
loss is traded against reducing the number of reagents required for detection. Using different
approaches to detection on a single platform provides orthogonal assay validation and allows the
investigator to quantify and compare performance against expenditure of resources.