Human Serum Albumin Detection Using QCM Immunosensor with Differential Frequency Measurement

摘要

In this paper, the Quartz Crystal Microbalance (QCM) immunosensor with differential frequency measurement is proposed. One of quartz crystal is used as a reference resonator to control experimental effects and other quartz crystals are used as detectors. The quartz crystals are oscillated by using individual Colpitts oscillator circuits with buffer amplifier. The reference resonator and detector crystal pairs are selected by using a multiplexer switch. Moreover, the detection of human serum albumin (HSA) ranging from 5 to 40 mg/L is investigated. The frequency shift after detector's surfaces immobilization with protein-A, anti-HSA, and l%casein are 184.16 ± 9.87, 239.14 ± 45.94, and 242.28 ±69.90 Hz, respectively. There is linear correlation between increasing of frequency shift and HSA concentration ranging from 5 to 40 mg/L. QCM immunosensor with differential frequency measurement show better correlation coefficient and resolution of detection (0.9839 and 0.071 ng/Hz, respectivly) than QCM immunosensor without differential frequency measurement (0.96345 and 0.1429 ng.Hz, respectivly). It is clear that the QCM immunosensor with differential fequency measument can improve HSA detection.