Screening-Limited Response of NanoBiosensors

Nair, Pradeep R.; Alam, Muhammad Ashraful

doi:10.1021/nl072593i

Cited by 222 publications

(202 citation statements)

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“…These distinct advantages are being explored for a variety of sensing applications in both liquid and gas phases [5][6][7][8] . In particular, chemical vapour sensing is uniquely positioned to elucidate the fundamental molecule-nanomaterial interaction and provide a test bed for evaluating nanoelectronic-sensing performance without interference from solvent background typically seen in liquid-based detection 9,10 . The current signal of a nanoelectronic sensor can in general be expressed as:…”

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confidence: 99%

Graphene nanoelectronic heterodyne sensor for rapid and sensitive vapour detection

et al. 2014

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Nearly all existing nanoelectronic sensors are based on charge detection, where molecular binding changes the charge density of the sensor and leads to sensing signal. However, intrinsically slow dynamics of interface-trapped charges and defect-mediated charge-transfer processes significantly limit those sensors' response to tens to hundreds of seconds, which has long been known as a bottleneck for studying the dynamics of molecule-nanomaterial interaction and for many applications requiring rapid and sensitive response. Here we report a fundamentally different sensing mechanism based on molecular dipole detection enabled by a pioneering graphene nanoelectronic heterodyne sensor. The dipole detection mechanism is confirmed by a plethora of experiments with vapour molecules of various dipole moments, particularly, with cis-and trans-isomers that have different polarities. Rapid (down to B0.1 s) and sensitive (down to B1 ppb) detection of a wide range of vapour analytes is achieved, representing orders of magnitude improvement over state-of-the-art nanoelectronics sensors.

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confidence: 99%

Graphene nanoelectronic heterodyne sensor for rapid and sensitive vapour detection

et al. 2014

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“…For example, the sensitivity of electrical nanobiosensors such as Si-Nanowire (NW) FET (field effect transistor) (Fig. 1B) is severely suppressed by the electrostatic screening due to the presence of other ions/charged biomolecules in the solution (7), which limits its sensitivity to vary linearly (in subthreshold regime) (3, 7) or logarithmically (in accumulation regime) (4,7,8,9) with respect to the captured molecule density N s . Moreover, the miniaturization and stability of the reference electrode have been a persistent problem, especially for lab-onchip applications (1).…”

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confidence: 99%

Flexure-FET biosensor to break the fundamental sensitivity limits of nanobiosensors using nonlinear electromechanical coupling

Jain

Nair

Alam

2012

Proc. Natl. Acad. Sci. U.S.A.

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In this article, we propose a Flexure-FET (flexure sensitive field effect transistor) ultrasensitive biosensor that utilizes the nonlinear electromechanical coupling to overcome the fundamental sensitivity limits of classical electrical or mechanical nanoscale biosensors. The stiffness of the suspended gate of Flexure-FET changes with the capture of the target biomolecules, and the corresponding change in the gate shape or deflection is reflected in the drain current of FET. The Flexure-FET is configured to operate such that the gate is biased near pull-in instability, and the FET-channel is biased in the subthreshold regime. In this coupled nonlinear operating mode, the sensitivity (S) of Flexure-FET with respect to the captured molecule density (N s ) is shown to be exponentially higher than that of any other electrical or mechanical biosensor.In other words, while S Flexure ∼ e ðγ 1 ffiffiffiffi N s p −γ 2 N s Þ , classical electrical or mechanical biosensors are limited to S classical ∼ γ 3 N S or γ 4 lnðN S Þ, where γ i are sensor-specific constants. In addition, the proposed sensor can detect both charged and charge-neutral biomolecules, without requiring a reference electrode or any sophisticated instrumentation, making it a potential candidate for various low-cost, point-of-care applications.label-free detection | genome sequencing | cantilever | spring-softening | critical-point sensors N anoscale biosensors are widely regarded as a potential candidate for ultrasensitive, label-free detection of biochemical molecules. Among the various technologies, significant research have focused on developing ultrasensitive nanoscale electrical (1) and mechanical (2) biosensors. Despite remarkable progress over the last decade, these technologies have fundamental challenges that limit opportunities for further improvement in their sensitivity ( Fig. 1A) (3-6). For example, the sensitivity of electrical nanobiosensors such as Si-Nanowire (NW) FET (field effect transistor) (Fig. 1B) is severely suppressed by the electrostatic screening due to the presence of other ions/charged biomolecules in the solution (7), which limits its sensitivity to vary linearly (in subthreshold regime) (3, 7) or logarithmically (in accumulation regime) (4,7,8,9) with respect to the captured molecule density N s . Moreover, the miniaturization and stability of the reference electrode have been a persistent problem, especially for lab-onchip applications (1). Finally, it is difficult to detect charge-neutral biological entities such as viruses or proteins using chargebased electrical nanobiosensor schemes.In contrast, nanomechanical biosensors like nanocantilevers (10, 11) (Fig. 1C) do not require biomolecules to be charged for detection. Here, the capture of target molecules on the cantilever surface modulates its mass, stiffness, and/or surface stress (5,11,12). This change in the mechanical properties of the cantilever can then be observed as a change in its resonance frequency (dynamic mode), mechanical deflection, or change in the resist...

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“…29) Therefore, the time taken to reach equilibrium, at which point a stable change in signal may be determined (referred to as the "settling time"), could be the one of the major performance limitations of biosensors. 30,31) Figure 4 shows the variation in channel current, measured at a constant voltage of 2 V, in Nisalicided Si-FET biosensors with and without antigencontaining peptide, as a function of measurement time. With increasing measurement time, the channel current with control PBS solution (no peptide) changes insignificantly.…”

Section: Resultsmentioning

confidence: 99%

Label-Free and Real-Time Immunodetection of the Avian Influenza A Hemagglutinin Peptide Using a Silicon Field-Effect Transistor Fabricated by a Nickel Self-Aligned Silicide Process

et al. 2012

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Electrical immunodetection of the avian influenza A (H5N1) hemagglutinin (HA) peptide, the IN peptide, with anti-HA antibody was demonstrated using a field-effect transistor (FET) with an n-type silicon (Si) channel and a nickel (Ni) self-aligned silicide source/drain that was fabricated by a conventional top-down process. The specific binding of the IN peptide with anti-HA antibody in phosphate buffered saline (PBS) occurs on the patterned SiO 2 surface through covalent linkage. Positive ions in the buffer create majority carriers in the n-type Si channel, leading to a rapid increase in current across that channel. However, specific binding of the negatively charged antigens on the SiO 2 surface overlaying the Si channel results in the reduction of electrons induced in the Si channel by the positive ions, causing a significant decrease in the channel current. The settling time for obtaining a stable signal change, driven by the negatively charged antigens bound to antibody, extrapolates to approximately 32 s.

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Screening-Limited Response of NanoBiosensors

Cited by 222 publications

References 19 publications

Graphene nanoelectronic heterodyne sensor for rapid and sensitive vapour detection

Graphene nanoelectronic heterodyne sensor for rapid and sensitive vapour detection

Flexure-FET biosensor to break the fundamental sensitivity limits of nanobiosensors using nonlinear electromechanical coupling

Label-Free and Real-Time Immunodetection of the Avian Influenza A Hemagglutinin Peptide Using a Silicon Field-Effect Transistor Fabricated by a Nickel Self-Aligned Silicide Process

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