The use of interdigitated electrodes and binding with Cibacron blue F3GA by self-assembly technology, which has high affinity for human serum albumin (HSA), and serves as a receptor for HSA detection, is reported. In preliminary tests, the interdigitated chip measured the impedance of HSA by electrochemical impedance spectroscopy and this result indicated the characteristic frequency of impedance change below 1.1 kHz. However, a portable capacitance measurement system made using a standard operational amplifier circuit and AC excitation was applied at 1 kHz. The detection result showed a significant linear correlation between HSA concentration (0.1 to 1 mg/ml) and output voltage. The regression equation was Y = 17.91 + 323.72X with R(2) = 0.999. This reported study has successfully demonstrated that the capacitive sensor has great potential for applications in HSA detection.
