Adsorption–desorption noise in microfluidic biosensors operating in multianalyte environments

Jokić, Ivana; Frantlović, Miloš; Djurić, Z.; Radulović, K.; Jokić, Zorana

doi:10.1016/j.mee.2015.02.032

Cited by 12 publications

(16 citation statements)

References 18 publications

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“…22,23,112 Another example for conventional FET-sensors is that the surface layer could be modified with a biomoleculepermeable polymer layer which is proposed to operate by extending the effective distance over which charges are screened within the layer. 113 A final example of particular interest is the use of frequency-mode detection, 15,46,[114][115][116][117] where the current response is measured in the frequency domain instead of the time-domain (details can be found in ESI 6 †). The lack of wide-spread adoption of alternative operating methods may be due to: complexity, with the additional required steps required making them less commercially appealing; a lack of awareness in a rapidly changing field; or lack of reproducibility.…”

Section: Recent Developmentsmentioning

confidence: 99%

Field-effect sensors – from pH sensing to biosensing: sensitivity enhancement using streptavidin–biotin as a model system

Lowe

Sun

Zeimpekis

et al. 2017

Analyst

136

107

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a Field-Effect Transistor sensors (FET-sensors) have been receiving increasing attention for biomolecular sensing over the last two decades due to their potential for ultra-high sensitivity sensing, label-free operation, cost reduction and miniaturisation. Whilst the commercial application of FET-sensors in pH sensing has been realised, their commercial application in biomolecular sensing (termed BioFETs) is hindered by poor understanding of how to optimise device design for highly reproducible operation and high sensitivity. In part, these problems stem from the highly interdisciplinary nature of the problems encountered in this field, in which knowledge of biomolecular-binding kinetics, surface chemistry, electrical double layer physics and electrical engineering is required. In this work, a quantitative analysis and critical review has been performed comparing literature FET-sensor data for pH-sensing with data for sensing of biomolecular streptavidin binding to surface-bound biotin systems. The aim is to provide the first systematic, quantitative comparison of BioFET results for a single biomolecular analyte, specifically streptavidin, which is the most commonly used model protein in biosensing experiments, and often used as an initial proofof-concept for new biosensor designs. This novel quantitative and comparative analysis of the surface potential behaviour of a range of devices demonstrated a strong contrast between the trends observed in pH-sensing and those in biomolecule-sensing. Potential explanations are discussed in detail and surfacechemistry optimisation is shown to be a vital component in sensitivity-enhancement. Factors which can influence the response, yet which have not always been fully appreciated, are explored and practical suggestions are provided on how to improve experimental design.

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Section: Recent Developmentsmentioning

confidence: 99%

Field-effect sensors – from pH sensing to biosensing: sensitivity enhancement using streptavidin–biotin as a model system

Lowe

Sun

Zeimpekis

et al. 2017

Analyst

136

107

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“…3,21 The EDL structure in turn can be affected by dense biomolecule layers through ion-exclusion; mathematical models incorporating ion-exclusion effects have been shown to describe experimental signal measurements of DNA hybridisation better than more conventional EDL models. 15 Recent experimental work recognises the importance of ion dynamics in BioFET engineering, with deterministic information extracted from BioFET signals in the frequency domain of the response 15,22,23 which has been explained as a result of adsorption-desorption noise of biomolecules 24 and perturbed charge fluctuations in the EDL. 25 Experiments have shown a decrease in low frequency noise with increased ionic strength due to increased screening competition between the EDL and the semiconductor device.…”

Section: Importance Of Edl Structure and Ion Dynamics In The Interfacmentioning

confidence: 99%

Dynamic behaviour of the silica-water-bio electrical double layer in the presence of a divalent electrolyte

Lowe

Maekawa

Shibuta

et al. 2017

Phys. Chem. Chem. Phys.

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Electronic devices are becoming increasingly used in chemical- and bio-sensing applications and therefore understanding the silica-electrolyte interface at the atomic scale is becoming increasingly important. For example, field-effect biosensors (BioFETs) operate by measuring perturbations in the electric field produced by the electrical double layer due to biomolecules binding on the surface. In this paper, explicit-solvent atomistic calculations of this electric field are presented and the structure and dynamics of the interface are investigated in different ionic strengths using molecular dynamics simulations. Novel results from simulation of the addition of DNA molecules and divalent ions are also presented, the latter of particular importance in both physiological solutions and biosensing experiments. The simulations demonstrated evidence of charge inversion, which is known to occur experimentally for divalent electrolyte systems. A strong interaction between ions and DNA phosphate groups was demonstrated in mixed electrolyte solutions, which are relevant to experimental observations of device sensitivity in the literature. The bound DNA resulted in local changes to the electric field at the surface; however, the spatial- and temporal-mean electric field showed no significant change. This result is explained by strong screening resulting from a combination of strongly polarised water and a compact layer of counterions around the DNA and silica surface. This work suggests that the saturation of the Stern layer is an important factor in determining BioFET response to increased salt concentration and provides novel insight into the interplay between ions and the EDL.

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“…For example, in [17] the authors assumed thermal noise of the equivalent impedance representing the charged antigen protein layer bound to the sensor's surface as the relevant noise source, obtaining Lorentzian-shaped spectral profiles. Other contributions were later introduced by considering mass transfer limitations [25], [28]- [30] and charge fluctuations across the Debye length [24], which result into additional and/or frequency shifted Lorentzian contributions with respect to the former model of [17]. Similar spectra have been calculated in [23], by solving numerically the mass transfer limited stochastic problem for affinity-based biosensors.…”

Section: Introductionmentioning

confidence: 99%

General Model and Equivalent Circuit for the Chemical Noise Spectrum Associated to Surface Charge Fluctuation in Potentiometric Sensors

2021

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This paper firstly reports a general and powerful approach to evaluate the power spectral density (PSD) of the surface charge fluctuations, so-called "chemical noise", from a generic set of reactions at the sensing surface of potentiometric sensors such as, for instance, Ion-Sensitive Field Effect Transistors (ISFETs). Starting from the master equation, the spectral noise signature of a reaction set is derived as a function of the reaction kinetic parameters and of the interface concentration of the ionic species. Secondly, we derive an equivalent surface admittance, whose thermal noise PSD produces a noise PSD equal to that of the surface charge fluctuations. We also show how to expand this surface admittance into staircase RC networks, with a number of elementary cells equal to the number of surface reactions involved. This admittance can be included in circuit simulations coupled with a SPICE compact model of the underlying FET, to enable the physically based modelling of frequency dispersion and noise of the sensing layer when simulating the sensor and the read-out. Validation with existing models and literature results as well as new application examples are provided. The proposed methodology to compute the PSD from rate equations is amenable to use in different contexts where fluctuations are generated by random transitions between discrete states with given exchange rates.

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Adsorption–desorption noise in microfluidic biosensors operating in multianalyte environments

Cited by 12 publications

References 18 publications

Field-effect sensors – from pH sensing to biosensing: sensitivity enhancement using streptavidin–biotin as a model system

Field-effect sensors – from pH sensing to biosensing: sensitivity enhancement using streptavidin–biotin as a model system

Dynamic behaviour of the silica-water-bio electrical double layer in the presence of a divalent electrolyte

General Model and Equivalent Circuit for the Chemical Noise Spectrum Associated to Surface Charge Fluctuation in Potentiometric Sensors

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