title: Label-free protein biosensor based on aptamer-modified carbon nanotube field-effect transistors.
abstract: We have fabricated label-free protein biosensors based on aptamer-modified carbon nanotube field-effect transistors (CNT-FETs) for the detection of immunoglobulin E (IgE). After the covalent immobilization of 5'-amino-modified 45-mer aptamers on the CNT channels, the electrical properties of the CNT-FETs were monitored in real time. The introduction of target IgE at various concentrations caused a sharp decrease in the source-drain current, and a gradual saturation was observed at lower concentrations. The amount of the net source-drain current before and after IgE introduction on the aptamer-modified CNT-FETs increased as a function of IgE concentration. The detection limit for IgE was determined as 250 pM. We have also prepared CNT-FET biosensors using a monoclonal antibody against IgE (IgE-mAb). The electrical properties of the aptamer- and antibody-modified CNT-FETs were compared. The performance of aptamer-modified CNT-FETs provided better results than the ones obtained using IgE-mAb-modified CNT-FETs under similar conditions. Thus, we suggest that the aptamer-modified CNT-FETs are promising candidates for the development of label-free protein biosensors.
authors.forename: Kenzo
authors.initials: K
authors.lastname: Maehashi
authors.forename: Taiji
authors.initials: T
authors.lastname: Katsura
authors.forename: Kagan
authors.initials: K
authors.lastname: Kerman
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Takamura
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Eiichi
authors.initials: E
authors.lastname: Tamiya
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D006801:Humans; D007073:Immunoglobulin E / Q000032:analysis*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011506:Proteins / Q000032:analysis
chemical_list: D052157:Aptamers, Nucleotide; D037742:Nanotubes, Carbon; D011506:Proteins; D007073:Immunoglobulin E