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Issue 33, 2019
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Quantum capacitance-limited MoS2 biosensors enable remote label-free enzyme measurements

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Abstract

We have demonstrated atomically thin, quantum capacitance-limited, field-effect transistors (FETs) that enable the detection of pH changes with 75-fold higher sensitivity (≈4.4 V per pH) over the Nernst value of 59 mV per pH at room temperature when used as a biosensor. The transistors, which are fabricated from monolayer films of MoS2, use a room temperature ionic liquid (RTIL) in place of a conventional oxide gate dielectric and exhibit very low intrinsic noise resulting in a pH resolution of 92 × 10−6 at 10 Hz. This high device performance, which is a function of the structure of our device, is achieved by remotely connecting the gate to a pH sensing element allowing the FETs to be reused. Because pH measurements are fundamentally important in biotechnology, the increased resolution demonstrated here will benefit numerous applications ranging from pharmaceutical manufacturing to clinical diagnostics. As an example, we experimentally quantified the function of the kinase Cdk5, an enzyme implicated in Alzheimer's disease, at concentrations that are 5-fold lower than physiological values, and with sufficient time-resolution to allow the estimation of both steady-state and kinetic parameters in a single experiment. The high sensitivity, increased resolution, and fast turnaround time of the measurements will allow the development of early diagnostic tools and novel therapeutics to detect and treat neurological conditions years before currently possible.

Graphical abstract: Quantum capacitance-limited MoS2 biosensors enable remote label-free enzyme measurements

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Supplementary files

Article information


Submitted
12 Apr 2019
Accepted
07 Aug 2019
First published
07 Aug 2019

Nanoscale, 2019,11, 15622-15632
Article type
Paper

Quantum capacitance-limited MoS2 biosensors enable remote label-free enzyme measurements

S. T. Le, N. B. Guros, R. C. Bruce, A. Cardone, N. D. Amin, S. Zhang, J. B. Klauda, H. C. Pant, C. A. Richter and A. Balijepalli, Nanoscale, 2019, 11, 15622
DOI: 10.1039/C9NR03171E

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