title: A carbon nanotube metal semiconductor field effect transistor-based biosensor for detection of amyloid-beta in human serum.
abstract: We have developed a carbon nanotube (CNT) film-based biosensor with a metal semiconductor field effect transistor structure (MESFET). A gold top gate was deposited on the middle of the CNT channel and probe antibodies were immobilized on the gold top gate with an antibody-binding protein, protein G or Escherichia coli outer membrane (OM) with autodisplayed Z-domains of protein A. These CNT-MESFET biosensors exhibited a higher sensitivity than the CNT-FET biosensor with probe antibodies immobilized using a chemical linker, since the orientation of immobilized antibodies was controlled by the antibody-binding proteins. In addition, nonspecific binding was effectively inhibited by E. coli OM. Using the CNT-MESFET biosensors with E. coli OM containing Z domain, we detected amyloid-β (Aβ) in human serum, one of the biomarkers for early diagnosis of Alzheimer's disease. Aβ at the level of 1 pg/mL in human serum could be measured in real-time and without labeling, which was lower than a limit of detection for plasma Aβ using an enzyme-linked immune sorbent assay. These results suggested that our CNT-MESFET biosensors might be applicable for an early diagnosis of Alzheimer's disease.
authors.affiliation: Nanomedical Graduate Program, Yonsei University, Seoul 120-749, Republic of Korea.
authors.forename: Jeseung
authors.initials: J
authors.lastname: Oh
authors.forename: Gu
authors.initials: G
authors.lastname: Yoo
authors.forename: Young Wook
authors.initials: YW
authors.lastname: Chang
authors.forename: Hyung Joon
authors.initials: HJ
authors.lastname: Kim
authors.forename: Joachim
authors.initials: J
authors.lastname: Jose
authors.forename: Eosu
authors.initials: E
authors.lastname: Kim
authors.forename: Jae-Chul
authors.initials: JC
authors.lastname: Pyun
authors.forename: Kyung-Hwa
authors.initials: KH
authors.lastname: Yoo
mesh_terms: D000544:Alzheimer Disease / Q000097:blood; D016229:Amyloid beta-Peptides / Q000097:blood*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D004926:Escherichia coli / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D037742:Nanotubes, Carbon / Q000737:chemistry*; D012666:Semiconductors
chemical_list: D016229:Amyloid beta-Peptides; D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; D037742:Nanotubes, Carbon; D006046:Gold
keywords: Alzheimer's disease; Amyloid-β; Biosensor; Carbon nanotube; E. coli outer membrane with autodisplayed Z-domain; Human serum; Metal semiconductor field effect transistor