Dielectrophoresis‐Based Protein Enrichment for a Highly Sensitive Immunoassay Using Ag/SiO<sub>2</sub> Nanorod Arrays

Cao, Zhen; Zhu, Yu; Liu, Yang; Dong, Shurong; Chen, Xin; Bai, Fan; Song, Shengxin; Fu, Junxue

doi:10.1002/smll.201703265

Cited by 33 publications

(38 citation statements)

References 38 publications

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“…(), these forces are expected to be miniscule for nanometer‐sized particles such as proteins. Nevertheless, negative protein DEP is indeed frequently observed experimentally for high frequencies [8, 13, 42, 45–47]. Apart from DEP contributions that rely on the polarization of the protein dipole, solvent‐mediated DEP forces that result from polarization‐induced changes of any other protein–water interaction are expected to persist at higher frequencies due to the faster dipolar response of water in the protein hydration shell.…”

Section: Discussionmentioning

confidence: 99%

Solvent‐mediated forces in protein dielectrophoresis

2021

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DEP is an established method to manipulate micrometer‐sized particles, but standard continuum theories predict only negligible effects for nanometer‐sized proteins despite contrary experimental evidence. A theoretical description of protein DEP needs to consider details on the molecular scale. Previous work toward this goal addressed the role of orientational polarization of static protein dipole moments for dielectrophoretic effects, which successfully predicts the general magnitude of dielectrophoretic forces on proteins but does not readily explain negative DEP forces observed for proteins in some experiments. However, contributions to the protein chemical potential due to protein–water interactions have not yet been considered in this context. Here, we utilize atomistic molecular dynamics simulations to evaluate polarization‐induced changes in the protein solvation free energy, which result in a solvent‐mediated contribution to dielectrophoretic forces. We quantify solvent‐mediated dielectrophoretic forces for two proteins and a small peptide in water, which follow expectations for protein–water dipole–dipole interactions. The magnitude of solvent‐mediated dielectrophoretic forces exceeds predictions of nonmolecular continuum theories, but plays a minor role for the total dielectrophoretic force for the simulated proteins due to dominant contributions from the orientational polarization of their static protein dipoles. However, we extrapolate that solvent‐mediated contributions to negative protein DEP forces will become increasingly relevant for multidomain proteins, complexes and aggregates with large protein–water interfaces, as well as for high electric field frequencies, which provides a potential mechanism for corresponding experimental observations of negative protein DEP.

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Section: Discussionmentioning

confidence: 99%

Solvent‐mediated forces in protein dielectrophoresis

2021

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“…developed an iDEP platform capable of rapidly enriching proteins for a high‐sensitivity immunoassay (Fig. 3B) [43]. The device was composed of a structure with 5 μm interelectrode gaps, where these gaps were filled with 100 nm nanorods on a 100 nm inter‐rod spacing.…”

Section: Biological Applicationsmentioning

confidence: 99%

Dielectrophoresis: Developments and applications from 2010 to 2020

et al. 2020

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The 20th century has seen tremendous innovation of dielectrophoresis (DEP) technologies, with applications being developed in areas ranging from industrial processing to micro‐ and nanoscale biotechnology. From 2010 to present day, there have been 981 publications about DEP. Of over 2600 DEP patents held by the United States Patent and Trademark Office, 106 were filed in 2019 alone. This review focuses on DEP‐based technologies and application developments between 2010 and 2020, with an aim to highlight the progress and to identify potential areas for future research. A major trend over the last 10 years has been the use of DEP techniques for biological and clinical applications. It has been used in various forms on a diverse array of biologically derived molecules and particles to manipulate and study them including proteins, exosomes, bacteria, yeast, stem cells, cancer cells, and blood cells. DEP has also been used to manipulate nano‐ and micron‐sized particles in order to fabricate different structures. The next 10 years are likely to see the increase in DEP‐related patent applications begin to result in a greater level of technology commercialization. Also during this time, innovations in DEP technology will likely be leveraged to continue the existing trend to further biological and medical‐focused applications as well as applications in microfabrication. As a tool leveraged by engineering and imaginative scientific design, DEP offers unique capabilities to manipulate small particles in precise ways that can help solve problems and enable scientific inquiry that cannot be addressed using conventional methods.

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“…7 and the video provided as supplementary material, all proteins within ± 1 pH unit of their isoelectric point (pI) and for zeta potentials less than 20 mV should exhibit negative DEP for frequencies up to 1 MHz. A DEP “cross‐over” above 1 MHz should be from negative to positive DEP, not the opposite effect observed for BSA [55], avidin [56], and prostate specific antigen (PSA) [57]. For zeta potential values above 40 mV, and at low ionic strengths of the electrolyte, a contribution to the +ve DEP observed for a protein is possible, but only in terms of it being a Maxwellian particle (until such time a new theory for protein DEP might prove otherwise).…”

Section: α‐Dispersion and Electrical Double Layermentioning

confidence: 99%

Protein dielectrophoresis: Key dielectric parameters and evolving theory

Hölzel

Pethig

2020

Electrophoresis

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Globular proteins exhibit dielectrophoresis (DEP) responses in experiments where the applied field gradient factor ∇E2 appears far too small, according to standard DEP theory, to overcome dispersive forces associated with the thermal energy kT of disorder. To address this a DEP force equation is proposed that replaces a previous empirical relationship between the macroscopic and microscopic forms of the Clausius–Mossotti factor. This equation relates the DEP response of a protein directly to the dielectric increment δε+ and decrement δε− that characterize its β‐dispersion at radio frequencies, and also indirectly to its intrinsic dipole moment by way of providing a measure of the protein's effective volume. A parameter Γpw, taken as a measure of cross‐correlated dipole interactions between the protein and its water molecules of hydration, is included in this equation. For 9 of the 12 proteins, for which an evaluation can presently be made, Γpw has a value of ≈4600 ± 120. These conclusions follow an analysis of the failure of macroscopic dielectric mixture (effective medium) theories to predict the dielectric properties of solvated proteins. The implication of a polarizability greatly exceeding the intrinsic value for a protein might reflect the formation of relaxor ferroelectric nanodomains in its hydration shell.

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Dielectrophoresis‐Based Protein Enrichment for a Highly Sensitive Immunoassay Using Ag/SiO₂ Nanorod Arrays

Cited by 33 publications

References 38 publications

Solvent‐mediated forces in protein dielectrophoresis

Solvent‐mediated forces in protein dielectrophoresis

Dielectrophoresis: Developments and applications from 2010 to 2020

Protein dielectrophoresis: Key dielectric parameters and evolving theory

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Dielectrophoresis‐Based Protein Enrichment for a Highly Sensitive Immunoassay Using Ag/SiO2 Nanorod Arrays

Cited by 33 publications

References 38 publications

Solvent‐mediated forces in protein dielectrophoresis

Solvent‐mediated forces in protein dielectrophoresis

Dielectrophoresis: Developments and applications from 2010 to 2020

Protein dielectrophoresis: Key dielectric parameters and evolving theory

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Product

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Dielectrophoresis‐Based Protein Enrichment for a Highly Sensitive Immunoassay Using Ag/SiO₂ Nanorod Arrays