Eight different miniaturised flow-through cell configurations with integrated capacitive EIS (electrolyte-insulator-semiconductor) structures have been fabricated at wafer level. The EIS structures have been prepared by means of Si technique (electron-beam evaporation, thermal dry oxidation) and serve as pH sensors. The channels for the miniaturised flow-through cell have been manufactured in SU-8 technique (spin-coating, exposure, developing, lift-off). The microcells have diameters of 200-2000 μm and volumes of 0.3-5 μl. The sensitive areas in the channels are ranging from 1.6 to 25 mm2. For the realisation of a biosensor, the enzyme penicillinase has been immobilised into the channels on the EIS sensor chip. The electrochemical characterisation of the sensor set-up has been performed by capacitance/voltage (C/V) and constant capacitance (ConCap) mode, respectively.
Schöning, M. J., Näther, N., Auger, V., Poghossian, A., & Koudelka-Hep, M. (2005). Miniaturised flow-through cell with integrated capacitive EIS sensor fabricated at wafer level using Si and SU-8 technologies. Sensors and Actuators, B: Chemical, 108(1-2), 986-992. https://doi.org/10.1016/j.snb.2004.12.029