Graphene Field Effect Transistor-Based Immunosensor for Ultrasensitive Noncompetitive Detection of Small Antigens
Yasushi Kanai, Yuki Ohmuro‐Matsuyama, Masami Tanioku, Shota Ushiba, Takao Ono, Kōichi Inoue, Tetsuya Kitaguchi, Masahiko Kimura, Hiroshi Ueda, Kazuhiko Matsumoto
Abstract
Due to its high carrier mobility, graphene is considered a suitable material for use in field-effect transistors. However, its application to immunosensing of small molecules is still elusive. To investigate the potential of graphene field effect transistors (G-FET) as a sensor for small molecules with small or no charge, we applied the open-sandwich immunoassay (OS-IA), which detects low-molecular-weight antigens noncompetitively, to G-FET. Using an antibody variable fragment VL immobilized on graphene and a hyperacidic region of amyloid precursor protein fused to the other variable fragment VH, we successfully detected a small antigen peptide consisting of 7 amino acids (BGP-C7), with a more than 100-fold increase in sensitivity compared with that measured by enzyme-linked OS-IA. Furthermore, we succeeded in detecting BGP-C7 in the presence of human serum with similar sensitivity, suggesting its potential application in clinical diagnostics.