Detection of Alpha-fetoprotein Concentration in Serum Using QCM-based Immunosensor.

• Main Authors: Ying-Chen Wu, 吳盈震
• Other Authors: I-Yu Huang
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/30719466776221367689

碩士 === 國立中山大學 === 電機工程學系研究所 === 96 === The α-fetoprotein (AFP) is an important tumor marker for detecting hepatocellular carcinoma (HCC), the second major cancer killers in Taiwan. This thesis utilized a high-sensitivity low-cost quartz crystal microbalance (QCM) to replace the conventional biochemical analysis to detect the extreme low concentration of AFP in human serum. In general, QCM-based biosensors or immunosensors require smaller volume of sample and fewer responding time than conventional analysis system. Once the AFP antibody has been successfully adsorbed on the surface of QCM, any AFP antigen bonded with it will change the output frequency of the QCM sensor. This research investigates the influence of the mass-sensitivity of QCM-AFP sensor on three surface-modification methods: (i) Adsorption method, (ii) Cystamine-Glutaldehyde (CA-GA) method and (iii) Cystamine (CA) method. The effects of the concentration of AFP antibody on the sensitivity also will be studied. The adsorption method shows an unstable adhesion than the other methods. The CA-GA method and CA method presents respectively the maximum binding ratio of AFP antibody/antigen pair at 0.1 mg/mL and 1.0 mg/mL AFP-antibody concentration. Under such condition, the high sensitivity and linearity of the CA-GA and CA methods equal to 0.142 (Hz mL mg-1)/99.8% and 0.35 (Hz mL mg-1)/98.2% can be demonstrated. Finally, this thesis uses a commerical AFM system to analyze the effective bonding area of the CA-GA and CA methods. The CA method shows a higher effective surface area than that of CA-GA method so it can present a higher mass-sensitivity of AFP-antigen.