Development of a sensor-array chip with immobilized antibodies and the application of a wireless antigen-screening system

The avidin molecule is composed of four domain structures, such that, four acceptors per molecule exist on the surface of the adsorbent particle. Biotin preferably interacts with this acceptor, because the molecular size of biotin is smaller that that of avidin. The sensor voltage changes do not suffer in the presence of cation contamination. In contrast, the molecular size of avidin is much larger than that of the cations in solution. In this respect, the cations are considered to interact with the sensor surface in preference to the biotin antibodies, thus promoting polarization of the insulator layer. As a result, the detection voltages increased, while the detection selectivity decreased.