| 초록 |
We report a method to build ultrasensitive carbon nanotube-based biosensors using immune binding reaction. Here, carbon nanotube-field effect transistors (CNT-FETs) were functionalized with antibody-binding fragments as a receptor, and the binding event of target IgG onto the fragments were detected by monitoring the gating effect caused by the charges of the target IgG. Since the biosensors were used in buffer solution, it was crucial to use small-size receptors so that the charged target IgG could approach CNT surface within the Debye length distance to give a large gating effect. The results show that CNT-FET biosensors using whole antibody had very low sensitivity (detection limit~1000 ng/mL), while those based on small Fab fragments could detect 1 pg/mL (~7fM level detection limit). Significantly, this strategy can be applied to general antibody-based detection schemes, and it should enable the production of label-free ultrasensitive electronic biosensors to detect clinically important biomarkers for disease diagnosis. |
