Overview and Research on Signal Readout Technology of Microcantilever Sensor

Since 1986, the first microcantilever applied in atomic force microscope, the device manufacturing technology, driving method and readout technology have improved significantly. In this paper, five readout technologies will be introduced in detail, and they are optical readout, piezoelectric readout, piezoresistive readout, capacitance readout and electron tunneling readout, respectively. Among them, the piezoresistive readout technology attracts a large number of researchers due to simple detection equipment, easy integration, and lower cost. In order to improve the detection accuracy of the piezoresistive microcantilever, a detection system based on FPGA is proposed in this paper. Output signal of the piezoresistive microcantilever array sensor for alpha-fetoprote (AFP) detection was researched. The detection accuracy of 0.05 Hz is achieved, the system stability is within 0.6 Hz, and it has a precise detection level for AFP with concentration of 50 pg/ml, which makes microcantilever has potential in early diagnosis and detection of liver cancer.