Field Effect Transistor Biosensor Using Antigen Binding Fragment for Detecting Tumor Marker in Human Serum

Materials

Shanshan Cheng¹  Kaori Hotani¹  Sho Hideshima²  Shigeki Kuroiwa²  Takuya Nakanishi²  Masahiro Hashimoto²  Yasuro Mori² 

[1] Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku-ku, Tokyo 169-8555, Japan; E-Mails:;Institute for Nanoscience & Nanotechnology, Waseda University, 513 Wasedatsurumaki-cho, Shinjuku-ku, Tokyo 162-0041, Japan; E-Mails:

关键词: antigen binding fragment;    label-free detection;    field effect transistor;    immunosensor;    Langmuir-type adsorption model;   

DOI  :  10.3390/ma7042490

来源: mdpi

【 摘 要 】

Detection of tumor markers is important for cancer diagnosis. Field-effect transistors (FETs) are a promising method for the label-free detection of trace amounts of biomolecules. However, detection of electrically charged proteins using antibody-immobilized FETs is limited by ionic screening by the large probe molecules adsorbed to the transistor gate surface, reducing sensor responsiveness. Here, we investigated the effect of probe molecule size on the detection of a tumor marker, α-fetoprotein (AFP) using a FET biosensor. We demonstrated that the small receptor antigen binding fragment (Fab), immobilized on a sensing surface as small as 2–3 nm, offers a higher degree of sensitivity and a wider concentration range (100 pg/mL–1 μg/mL) for the FET detection of AFP in buffer solution, compared to the whole antibody. Therefore, the use of a small Fab probe molecule instead of a whole antibody is shown to be effective for improving the sensitivity of AFP detection in FET biosensors. Furthermore, we also demonstrated that a Fab-immobilized FET subjected to a blocking treatment, to avoid non-specific interactions, could sensitively and selectively detect AFP in human serum.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland