Interdigital Capacitive Bio-sensor

• Main Authors: Yi-shan Lee, 李易珊
• Other Authors: Yue-ming Hsin
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/93886714869913084014

碩士 === 國立中央大學 === 電機工程研究所 === 98 === This research focused on developing a capacitance type biosensor for human serum albumin (HSA) detection. An interdigital electrode was designed in early study, with fabrication on printed circuit board (PCB) technique. The measurement and analysis of interdigital electrodes under different HSA concentrations were to observe the capacitance, resistance, impedance and phase variation. The measurement results showed a semi-log correlation between the measured data and the concentrations of HSA from 0.01 mg/ml to 1 mg/ml. The regression equation was y = -0.0344 Ln(x) + 0.5366 on measured capacitance, y =139.11 Ln(x) + 834.8 on measured resistance, y = 23.103 Ln(x) + 305.78 on measured impedance, y = -2.7804 Ln(x) - 71.16 on measured phase. In order to integrate the interdigital electrode and detection system, the capacitor bio-sensing oscillator circuit was designed by using TSMC CMOS process from CIC. The detection method adopted in this oscillator circuit is variable capacitance sensing, the variable capacitance is related to the dielectric constant in-between the interdigital capacitor which is changed by different liquids, and the oscillator frequency thus changed accordingly by LC tank or ring oscillator.