Dual-gate polysilicon nanoribbon biosensors enable high sensitivity detection of proteins

Zeimpekis, I., Sun, K., Hu, C. , Ditshego, N.M.J., Thomas, O., de Planque, M.R.R., Chong, H.M.H., Morgan, H. and Ashburn, P. (2016) Dual-gate polysilicon nanoribbon biosensors enable high sensitivity detection of proteins. Nanotechnology, 27(16), p. 165502. (doi: 10.1088/0957-4484/27/16/165502) (PMID:26954011)

Abstract

We demonstrate the advantages of dual-gate polysilicon nanoribbon biosensors with a comprehensive evaluation of different measurement schemes for pH and protein sensing. In particular, we compare the detection of voltage and current changes when top- and bottom-gate bias is applied. Measurements of pH show that a large voltage shift of 491 mV pH−1 is obtained in the subthreshold region when the top-gate is kept at a fixed potential and the bottom-gate is varied (voltage sweep). This is an improvement of 16 times over the 30 mV pH−1 measured using a top-gate sweep with the bottom-gate at a fixed potential. A similar large voltage shift of 175 mV is obtained when the protein avidin is sensed using a bottom-gate sweep. This is an improvement of 20 times compared with the 8.8 mV achieved from a top-gate sweep. Current measurements using bottom-gate sweeps do not deliver the same signal amplification as when using bottom-gate sweeps to measure voltage shifts. Thus, for detecting a small signal change on protein binding, it is advantageous to employ a double-gate transistor and to measure a voltage shift using a bottom-gate sweep. For top-gate sweeps, the use of a dual-gate transistor enables the current sensitivity to be enhanced by applying a negative bias to the bottom-gate to reduce the carrier concentration in the nanoribbon. For pH measurements, the current sensitivity increases from 65% to 149% and for avidin sensing it increases from 1.4% to 2.5%.

• Item Type: Articles
• Additional Information: The authors would like to acknowledge the Technology Strategy Board (TSB) and the Engineering and Physical Sciences Research Council (EPSRC: EP/K502327/1) for funding this work.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hu, Dr Chunxiao
• Authors: Zeimpekis, I., Sun, K., Hu, C., Ditshego, N.M.J., Thomas, O., de Planque, M.R.R., Chong, H.M.H., Morgan, H., and Ashburn, P.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Nanotechnology
• Publisher: IOP Publishing
• ISSN: 0957-4484
• ISSN (Online): 1361-6528
• Published Online: 08 March 2016