Calculation of the Response of Field-Effect Transistors to Charged Biological Molecules

Landheer, D.; McKinnon, W. R.; Aers, G. C.; Jiang, Weihong; Deen, M. Jamal; Shinwari, M. Waleed

doi:10.1109/jsen.2007.901047

Cited by 59 publications

(42 citation statements)

References 17 publications

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“…It thus becomes imperative to consider both layer thickness and different screening properties within these molecular layers to validate and predict experimental observations. Recent reports that have considered screening properties within DNA layers attribute the mechanisms of signal generation to either ion exclusion, formation of a Donnan membrane potential, or differences in permittivity [10][11][12][13][14][15][16][17] between the DNA and electrolyte phase. Most of these studies have been theoretical in nature with very little experimental corroboration.…”

Section: Dna Addition Is Thenmentioning

confidence: 99%

Programmable ion-sensitive transistor interfaces. III. Design considerations, signal generation, and sensitivity enhancement

et al. 2014

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We report on factors that affect DNA hybridization detection using ion-sensitive field-effect transistors (ISFETs). Signal generation at the interface between the transistor and immobilized biomolecules is widely ascribed to unscreened molecular charges causing a shift in surface potential and hence the transistor output current. Traditionally, the interaction between DNA and the dielectric or metal sensing interface is modeled by treating the molecular layer as a sheet charge and the ionic profile with a Poisson-Boltzmann distribution. The surface potential under this scenario is described by the Graham equation. This approximation, however, often fails to explain large hybridization signals on the order of tens of mV. More realistic descriptions of the DNA-transistor interface which include factors such as ion permeation, exclusion, and packing constraints have been proposed with little or no corroboration against experimental findings. In this study, we examine such physical models by their assumptions, range of validity, and limitations. We compare simulations against experiments performed on electrolyte-oxide-semiconductor capacitors and foundry-ready floating-gate ISFETs. We find that with weakly charged interfaces (i.e., low intrinsic interface charge), pertinent to the surfaces used in this study, the best agreement between theory and experiment exists when ions are completely excluded from the DNA layer. The influence of various factors such as bulk pH, background salinity, chemical reactivity of surface groups, target molecule concentration, and surface coatings on signal generation is studied. Furthermore, in order to overcome Debye screening limited detection, we suggest two signal enhancement strategies. We first describe frequency domain biosensing, highlighting the ability to sort short DNA strands based on molecular length, and then describe DNA biosensing in multielectrolytes comprising trace amounts of higher-valency salt in a background of monovalent saline. Our study provides guidelines for optimized interface design, signal enhancement, and the interpretation of FET-based biosensor signals.

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Section: Dna Addition Is Thenmentioning

confidence: 99%

Programmable ion-sensitive transistor interfaces. III. Design considerations, signal generation, and sensitivity enhancement

et al. 2014

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“…It would enable detection of extremely small concentrations of target DNA in a solution, eliminating the need for overcomplicated PCR (Polymerase Chain Reaction) tests, allowing rapid analysis and early pathogen detection. And it is the early detection, as well as the control of outbreaks, that are major cornerstones of the contemporary biosensor research [120][121][122][123] .…”

Section: Medical Applications Of Single Molecule Conductancementioning

confidence: 99%

Electrical Conductance in Biological Molecules

Shinwari

Deen

Starikov

et al. 2010

Adv Funct Materials

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Nucleic acids and proteins are not only biologically important polymers: They have recently been recognized as novel functional materials surpassing in many aspects the conventional ones. Although Herculean efforts have been undertaken to unravel fine functioning mechanisms of the biopolymers in question, there is still much more to be done. This particular paper presents the topic of biomolecular charge transport, with a particular focus on charge transfer/transport in DNA and protein molecules. Here the experimentally revealed details, as well as the presently available theories, of charge transfer/transport along these biopolymers are critically reviewed and analyzed. A summary of the active research in this field is also given, along with a number of practical recommendations.)Received: ((will be filled in by the editorial staff))Revised: ((will be filled in by the editorial staff))

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“…The PB equations for the electrolyte region and DNA membrane region are given by [8,9] (3a) These equations can be solved to give the surface potential of the electrolyte, denoted by ψ 0 .…”

Section: Electrical Model Of Cnnfetmentioning

confidence: 99%

Analysis of Sensing Mechanisms in a Gold-Decorated SWNT Network DNA Biosensor

Ahn¹,

Kim²,

Lim³

et al. 2014

JSTS:Journal of Semiconductor Technology and Science

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Abstract-We show that carbon nanotube sensors with gold particles on the single-walled carbon nanotube (SWNT) network operate as Schottky barrier transistors, in which transistor action occurs primarily by varying the resistance of Au-SWNT junction rather than the channel conductance modulation. Transistor characteristics are calculated for the statistically simplified geometries, and the sensing mechanisms are analyzed by comparing the simulation results of the MOSFET model and Schottky junction model with the experimental data. We demonstrated that the semiconductor MOSFET effect cannot explain the experimental phenomena such as the very low limit of detection (LOD) and the logarithmic dependence of sensitivity to the DNA concentration. By building an asymmetric concentricelectrode model which consists of serially-connected segments of CNTFETs and Schottky diodes, we found that for a proper explanation of the experimental data, the work function shifts should be ~ 0.1 eV for 100 pM DNA concentration and ~ 0.4 eV for 100 µM.

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Calculation of the Response of Field-Effect Transistors to Charged Biological Molecules

Cited by 59 publications

References 17 publications

Programmable ion-sensitive transistor interfaces. III. Design considerations, signal generation, and sensitivity enhancement

Programmable ion-sensitive transistor interfaces. III. Design considerations, signal generation, and sensitivity enhancement

Electrical Conductance in Biological Molecules

Analysis of Sensing Mechanisms in a Gold-Decorated SWNT Network DNA Biosensor

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