Field effect transistor biosensor using antigen binding fragment for detecting tumor marker in human serum

Shanshan Cheng, Kaori Hotani, Sho Hideshima, Shigeki Kuroiwa, Takuya Nakanishi, Masahiro Hashimoto, Yasuro Mori, Tetsuya Osaka*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

65 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)2490-2500
Number of pages11
Issue number4
Publication statusPublished - 2014


  • Antigen binding fragment
  • Field effect transistor
  • Immunosensor
  • Label-free detection
  • Langmuir-type adsorption model

ASJC Scopus subject areas

  • Materials Science(all)


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