Simultaneous Determination of Linear and Nonlinear Electrophoretic Mobilities of Cells and Microparticles

Antunez-Vela, Sofia; Pérez-González, Víctor H.; Peña, Adriana Coll De; Lentz, Cody J.; Lapizco‐Encinas, Blanca H.

doi:10.1021/acs.analchem.0c03525

Cited by 35 publications

(71 citation statements)

References 32 publications

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“…At lower electric fields, linear EK, the superposition of EO and EP (1) dominates particle migration. The expressions for the linear EK phenomena are as follows [7]:…”

Section: Theorymentioning

confidence: 99%

“…In recent years, there has been significant progress in the development of microscale electrokinetic EK methodologies for the identification, separation, enrichment, analysis, and detection of a wide array of bioparticles, ranging from macromolecules to parasites [3][4][5][6]. Furthermore, EK devices offer the unique potential of being able to exploit both linear and nonlinear EK phenomena [7,8] within the same system, leading to highly selective and discriminatory separation and purification processes [9,10].…”

Section: Introductionmentioning

confidence: 99%

“…The great majority of EK injection schemes have been designed for capillary systems or microchannel systems that do not feature any type of structure within the capillary or the microchannel. The present study was focused on the development of optimized EK injection schemes for direct current insulator-based EK (DC-iEK) systems [7,8]. These are microchannels that contain arrays of insulating structures, and the presence of these structures generates a nonuniform distribution of the electric field when a potential is applied across the channel [21,22].…”

Section: Introductionmentioning

confidence: 99%

“…This is especially critical for the second step of the injection, gating, as it is when the particles are first introduced to the post array (separation channel) where the particle experience greater electric fields induced by the constrictions of the post array. Recently, there was a major discovery in the field of DC-iEK systems, as it was demonstrated that dielectrophoresis (DEP) was not the major EK force responsible of particle trapping and manipulation in these systems [7,23]. Particle trapping and enrichment in DC-iEK are mainly the result of the balance between electroosmosis (EO) and linear and nonlinear electrophoresis (EP (1) and EP (3) , respectively) [7,23].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, there was a major discovery in the field of DC-iEK systems, as it was demonstrated that dielectrophoresis (DEP) was not the major EK force responsible of particle trapping and manipulation in these systems [7,23]. Particle trapping and enrichment in DC-iEK are mainly the result of the balance between electroosmosis (EO) and linear and nonlinear electrophoresis (EP (1) and EP (3) , respectively) [7,23]. There are two main particle EK migration regimes in iEK systems: particle streaming and particle trapping.…”

Section: Introductionmentioning

confidence: 99%

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Fine-Tuning Electrokinetic Injections Considering Nonlinear Electrokinetic Effects in Insulator-Based Devices

et al. 2021

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The manner of sample injection is critical in microscale electrokinetic (EK) separations, as the resolution of a separation greatly depends on sample quality and how the sample is introduced into the system. There is a significant wealth of knowledge on the development of EK injection methodologies that range from simple and straightforward approaches to sophisticated schemes. The present study focused on the development of optimized EK sample injection schemes for direct current insulator-based EK (DC-iEK) systems. These are microchannels that contain arrays of insulating structures; the presence of these structures creates a nonuniform electric field distribution when a potential is applied, resulting in enhanced nonlinear EK effects. Recently, it was reported that the nonlinear EK effect of electrophoresis of the second kind plays a major role in particle migration in DC-iEK systems. This study presents a methodology for designing EK sample injection schemes that consider the nonlinear EK effects exerted on the particles being injected. Mathematical modeling with COMSOL Multiphysics was employed to identify proper voltages to be used during the EK injection process. Then, a T-microchannel with insulating posts was employed to experimentally perform EK injection and separate a sample containing two types of similar polystyrene particles. The quality of the EK injections was assessed by comparing the resolution (Rs) and number of plates (N) of the experimental particle separations. The findings of this study establish the importance of considering nonlinear EK effects when planning for successful EK injection schemes.

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“…At lower electric fields, linear EK, the superposition of EO and EP (1) dominates particle migration. The expressions for the linear EK phenomena are as follows [7]:…”

Section: Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Fine-Tuning Electrokinetic Injections Considering Nonlinear Electrokinetic Effects in Insulator-Based Devices

et al. 2021

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Review of nonlinear electrokinetic flows in insulator‐based dielectrophoresis: From induced charge to Joule heating effects

Xuan

2021

Electrophoresis

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Insulator‐based dielectrophoresis (iDEP) has been increasingly used for particle manipulation in various microfluidic applications. It exploits insulating structures to constrict and/or curve electric field lines to generate field gradients for particle dielectrophoresis. However, the presence of these insulators, especially those with sharp edges, causes two nonlinear electrokinetic flows, which, if sufficiently strong, may disturb the otherwise linear electrokinetic motion of particles and affect the iDEP performance. One is induced charge electroosmotic (ICEO) flow because of the polarization of the insulators, and the other is electrothermal flow because of the amplified Joule heating in the fluid around the insulators. Both flows vary nonlinearly with the applied electric field (either DC or AC) and exhibit in the form of fluid vortices, which have been utilized to promote some applications while being suppressed in others. The effectiveness of iDEP benefits from a comprehensive understanding of the nonlinear electrokinetic flows, which is complicated by the involvement of the entire iDEP device into electric polarization and thermal diffusion. This article is aimed to review the works on both the fundamentals and applications of ICEO and electrothermal flows in iDEP microdevices. A personal perspective of some future research directions in the field is also given.

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Particle trapping in electrically driven insulator‐based microfluidics: Dielectrophoresis and induced‐charge electrokinetics

Pérez-González

2021

Electrophoresis

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Electrokinetically driven insulator-based microfluidic devices represent an attractive option to manipulate particle suspensions. These devices can filtrate, concentrate, separate, or characterize micro and nanoparticles of interest. Two decades ago, inspired by electrodebased dielectrophoresis, the concept of insulator-based dielectrophoresis (iDEP) was born. In these microfluidic devices, insulating structures (i.e., posts, membranes, obstacles, or constrictions) built within the channel are used to deform the spatial distribution of an externally generated electric field. As a result, particles suspended in solution experience dielectrophoresis (DEP). Since then, it has been assumed that DEP is responsible for particle trapping in these devices, regardless of the type of voltage being applied to generate the electric field-direct current (DC) or alternating current. Recent findings challenge this assumption by demonstrating particle trapping and even particle flow reversal in devices that prevent DEP from occurring (i.e., unobstructed long straight channels stimulated with a DC voltage and featuring a uniform electric field). The theory introduced to explain those unexpected observations was then applied to conventional "DC-iDEP" devices, demonstrating better prediction accuracy than that achieved with the conventional DEP-centered theory. This contribution summarizes contributions made during the last two decades, comparing both theories to explain particle trapping and highlighting challenges to address in the near future.

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Simultaneous Determination of Linear and Nonlinear Electrophoretic Mobilities of Cells and Microparticles

Cited by 35 publications

References 32 publications

Fine-Tuning Electrokinetic Injections Considering Nonlinear Electrokinetic Effects in Insulator-Based Devices

Fine-Tuning Electrokinetic Injections Considering Nonlinear Electrokinetic Effects in Insulator-Based Devices

Review of nonlinear electrokinetic flows in insulator‐based dielectrophoresis: From induced charge to Joule heating effects

Particle trapping in electrically driven insulator‐based microfluidics: Dielectrophoresis and induced‐charge electrokinetics

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