We have fabricated label-free protein biosensors based on aptamer-modified carbon nanotube field-effect transistors (CNTFET) for detection of immunoglobulin E (IgE). Since aptamers are artificial oligonucleotides, the aptamers are smaller in size than the Debye length. Therefore, the biosensors are expected to detect IgE with high sensitivity and high selectivity. After the 5’- amino modified aptamers were covalently immobilized on the CNT channels, the electrical properties of the CNTFETs were monitored in real time. The introduction of target IgE at various concentrations caused a sharp decrease in the source-drain current and gradual saturation at lower values. The amount of the net source-drain current before and after IgE introduction increased as a function of IgE concentration. Therefore, IgE at 250 pM could be effectively detected. Aptamer-modified CNTFETs are a promising candidate for label-free protein biosensors.
Journal: TechConnect Briefs
Volume: 2, Technical Proceedings of the 2007 NSTI Nanotechnology Conference and Trade Show, Volume 2
Published: May 20, 2007
Pages: 202 - 205
Industry sector: Medical & Biotech
Topic: Diagnostics & Bioimaging