IEF in microfluidic devices

Sommer, Gregory J; Hatch, Anson V.

doi:10.1002/elps.200800598

Cited by 57 publications

(70 citation statements)

References 85 publications

(84 reference statements)

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“…46,82,83 Hydrogels provide a hydrated environment for proteins so that native activity or functionality can often be maintained. 102 A disadvantage of hydrogels is the fragility of some gel structures (i.e., application of shear forces or high electric fields can damage the structure 135 ). Once formed, a stationary hydrogel is difficult to remove from the channel if regeneration of the assay system is needed.…”

Section: Hydrogelmentioning

confidence: 99%

Protein immobilization techniques for microfluidic assays

2013

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Microfluidic systems have shown unequivocal performance improvements over conventional bench-top assays across a range of performance metrics. For example, specific advances have been made in reagent consumption, throughput, integration of multiple assay steps, assay automation, and multiplexing capability. For heterogeneous systems, controlled immobilization of reactants is essential for reliable, sensitive detection of analytes. In most cases, protein immobilization densities are maximized, while native activity and conformation are maintained. Immobilization methods and chemistries vary significantly depending on immobilization surface, protein properties, and specific assay goals. In this review, we present trade-offs considerations for common immobilization surface materials. We overview immobilization methods and chemistries, and discuss studies exemplar of key approaches—here with a specific emphasis on immunoassays and enzymatic reactors. Recent “smart immobilization” methods including the use of light, electrochemical, thermal, and chemical stimuli to attach and detach proteins on demand with precise spatial control are highlighted. Spatially encoded protein immobilization using DNA hybridization for multiplexed assays and reversible protein immobilization surfaces for repeatable assay are introduced as immobilization methods. We also describe multifunctional surface coatings that can perform tasks that were, until recently, relegated to multiple functional coatings. We consider the microfluidics literature from 1997 to present and close with a perspective on future approaches to protein immobilization.

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Section: Hydrogelmentioning

confidence: 99%

Protein immobilization techniques for microfluidic assays

2013

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“…In conventional CIEF, however, the focused analytes must be transported toward a detection window, which can sometimes decrease the resolution due to a band broadening during transportation [5]. Recently, many IEF techniques using microfluidic devices (microfluidic IEF, MIEF) have been developed to overcome this drawback [6][7][8][9][10][11][12]. MIEF has many advantages compared to CIEF, including a short analysis time (within 5 min) due to a short separation channel (several cm) and the requirement of a minimal amount of reagents and samples (several L).…”

Section: Introductionmentioning

confidence: 99%

A Simple and Easy-to-Use Capillary Isoelectric Focusing Technique Using Reagent-Release Hydrogels

et al. 2017

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Reagent-release hydrogels containing an acid or a base solution were prepared and employed as ion suppliers in isoelectric focusing using short capillaries. In conventional isoelectric focusing techniques using microfluidic channels, complicated liquid manipulations are required, which can decrease analytical performance such as the reproducibility of a focusing position. To develop a rapid and sensitive assay based on microfluidic isoelectric focusing, we previously prepared reagent-release capillaries retaining ampholytes by physical adsorption on the inner surface of a short capillary, which were then applied to isoelectric focusing. In this study, reagent-release hydrogels containing an acid or a base solution were developed for isoelectric focusing using short capillaries in place of the acid and base solutions used in conventional microfluidic isoelectric focusing. The prepared reagent-release hydrogels showed some advantages for isoelectric focusing, e.g., high durability for at least five weeks of storage, easy handling as compared to the conventional solutions, and suppression of hydrodynamic flow in capillaries, which often decreases the reproducibility in capillary isoelectric focusing. The migration behavior of ions from the hydrogels into the capillary and the formation of a pH gradient in isoelectric focusing using the reagent-release hydrogels were investigated, which confirmed that the prepared reagent-release hydrogels could form a similar pH gradient to that obtained with conventional capillary isoelectric focusing using the solutions.

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“…CZE, MBE, and ITP are based on the displacement of electrophoretic species along the microchannel. IEF allows amphoteric component to focus at its stable isoelectric point (pI) in a predefined pH gradient (Sommer and Hatch 2009). Free flow methods, such as FFE or free flow IEF (FFIEF), employ transverse electric fields in relation to the flow Electronic supplementary material The online version of this article (doi:10.1007/s10404-010-0660-x) contains supplementary material, which is available to authorized users.…”

Section: Introductionmentioning

confidence: 99%

Modeling and high performance simulation of electrophoretic techniques in microfluidic chips

Kler

Berli

Guarnieri

2010

Microfluid Nanofluid

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Electrophoretic separations comprise a group of analytical techniques such as capillary zone electrophoresis, isoelectric focusing, isotachophoresis, and free flow electrophoresis. These techniques have been miniaturized in the last years and now represent one of the most important applications of the lab-on-a-chip technology. A 3D and time-dependent numerical model of electrophoresis on microfluidic devices is presented. The model is based on the set of equations that governs electrical phenomena, fluid dynamics, mass transport, and chemical reactions. The relationship between the buffer characteristics (ionic strength and pH) and surface potential of channel walls is taken into consideration. Numerical calculations were performed by using PETSc-FEM, in a Python environment, employing high performance parallel computing. The method includes a set of last generation preconditioners and solvers, especially addressed to 3D microfluidic problems, which significantly improve the numerical efficiency in comparison with typical commercial software for multiphysics. In this work, after discussing two validation examples, the numerical prototyping of a microfluidic chip for twodimensional electrophoresis is presented.

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IEF in microfluidic devices

Cited by 57 publications

References 85 publications

Protein immobilization techniques for microfluidic assays

Protein immobilization techniques for microfluidic assays

A Simple and Easy-to-Use Capillary Isoelectric Focusing Technique Using Reagent-Release Hydrogels

Modeling and high performance simulation of electrophoretic techniques in microfluidic chips

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