Abstract
This paper presents a simple and sensitive method for the real-time detection of a prostate cancer marker (PSA-ACT complex) through label-free protein biosensors based on a carbon nanotube field effect transistor (CNT-FET). Herein, the CNT-FET was functionalized with a solution containing various linker-to-spacer ratios, the binding event of the target PSA-ACT complex onto the receptor detected by monitoring the gating effect caused by charges in the target PSA-ACT complex. Since the biosensors were used in a buffer solution, it was crucial to control the distance between the receptors through introduction of linkers and spacers so that the charged target PSA-ACT complex could easily approach the CNT surface within the Debye length to give a large gating effect. The results show that CNT-FET biosensors modified with only linkers could not detect target proteins unless a very high concentration of the PSA-ACT complex solution (∼500 ng/ml) was injected, while those modified with a 1:3 ratio of linker-to-spacer could detect 1.0 ng/ml without any pretreatment. Moreover, our linker and spacer-modified CNT-FET could successfully block non-target proteins and selectively detect the target protein in human serum. Significantly, this strategy can be applied to general antibody-based detection schemes and enables production of very simple and sensitive electronic biosensors to detect clinically important biomarkers for disease diagnosis.
Original language | English |
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Pages (from-to) | 3372-3378 |
Number of pages | 7 |
Journal | Biosensors and Bioelectronics |
Volume | 24 |
Issue number | 11 |
DOIs | |
Publication status | Published - 2009 Jul 15 |
Externally published | Yes |
Keywords
- Biosensor
- Carbon nanotube
- Field effect transistor
- Prostate cancer
- Spacer
- Surface modification
ASJC Scopus subject areas
- Biotechnology
- Biophysics
- Biomedical Engineering
- Electrochemistry