Labelfree fully electronic nucleic acid detection system based on a field-effect transistor device

The possibility of exposure to botulinum neurotoxin (BoNT), a powerful and potential bioterrorism agent, is considered to be ever increasing. The current gold-standard assay, live-mouse lethality, exhibits high sensitivity but has limitations including long assay times, whereas other assays evince rapidity but lack factors such as real-time monitoring or portability. In this study, we aimed to devise a novel detection system that could detect BoNT at below-nanomolar concentrations in the form of a stretchable biosensor. We used a field-effect transistor with a p-type channel and electrodes, along with a channel comprising aligned carbon nanotube layers to detect the type E light chain of BoNT (BoNT/E-Lc). The detection of BoNT/E-Lc entailed observing the cleavage of a unique peptide and the specific bonding between BoNT/E-Lc and antibody BoNT/E-Lc (Anti-BoNT/E-Lc). The unique peptide was cleaved by 60 pM BoNT/E-Lc; notably, 52 fM BoNT/E-Lc was detected within 1 min in the device with the antibody in the bent state. These results demonstrated that an all-carbon nanotube-based device (all-CNT-based device) could be produced without a complicated fabrication process and could be used as a biosensor with high sensitivity, suggesting its potential development as a wearable BoNT biosensor.

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Electronic Detection of Nucleic Acid Molecules with a Field-Effect Transistor

MRS Proceedings ◽

10.1557/proc-828-a6.9 ◽

2004 ◽

Vol 828 ◽

Cited By ~ 2

Author(s):

Sven Ingebrandt ◽

Yinhua Han ◽

Malla-Reddy Sakkari ◽

Regina Stockmann ◽

Oleksandr Belinskyy ◽

...

Keyword(s):

Nucleic Acid ◽

Dna Sequences ◽

Field Effect ◽

Field Effect Transistor ◽

Electrochemical Impedance ◽

Oxide Semiconductor ◽

Readout System ◽

Dna Chips ◽

Electronic Detection ◽

Effect Transistor

ABSTRACTCurrently, systems for the detection of nucleic acid sequences, known as DNA-chips, are getting lots of attention. Such systems usually involve either an enzymatic or chemical labelling reaction as part of the detection process. The next generation of DNA-chips aims at a labelfree, fully electronic readout system. Several new approaches to signal generation that avoid a labelling step have been developed in recent years. Besides other surface sensitive measurements the possibility of electrochemical impedance and field-effect measurements for the detection of biomolecules have been discussed. The fully electronic detection of charged biomolecules based on the field-effect principle offers a labelfree method, which combines the unique sensitivity and selectivity of biomolecular recognition reactions with an electronic chip-based readout. In this approach one type of molecules is fixed at a surface and the biomolecular reaction with complementary molecules is detected by change in the drain-source current of the transistor. This change can occur by a change of the interface capacitance of the transistor gate or by change of the surface potential during adsorption of the molecules. At the moment a complete theoretical description of the detection principle is still under discussion. However, the fully electronic readout of biomolecular reactions offers a unique principle for the construction of many different sensors for bioassays. We are working on an approach to detect the hybridization of DNA sequences using electrolyte-oxide-semiconductor field-effect transistor (EOSFET) arrays. This method allows direct and in situ detection of specific DNA sequences without any labelling.

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