Micro free flow electrophoresis

Johnson, Alexander C.; Bowser, Michael T.

doi:10.1039/c7lc01105a

Cited by 50 publications

(38 citation statements)

References 83 publications

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“…13 electrophoresis devices, the diffusive broadening effect decreases with increased flow while the hydrodynamic broadening effect decreases with decreased flow and as such, there is an optimum flow rate at which the overall broadening effect can be minised. 9,15 In contrast, for the devices described here both the diffusive and the hydrodynamic broadening contributions decrease with increasing flow rate. This generates the possibility to, in principle, remove all of the broadening effect from these two sources rather than operate the devices under conditions which achieve a compromise between the two effects but do not give the option to simultaneously prevent them.…”

Section: Optical Detection In the Deep Uv-wavelength Regionmentioning

confidence: 66%

Enhancing the Resolution of Micro Free Flow Electrophoresis through Spatially Controlled Sample Injection

Saar

Müller²,

Charmet

et al. 2018

Anal. Chem.

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Free flow electrophoresis is a versatile technique for the continuous separation of mixtures with both preparative and analytical applications. Microscale versions of free flow electrophoresis are particularly attractive strategies because of their fast separation times, ability to work with small sample volumes, and large surface area to volume ratios facilitating rapid heat transfer, thus minimizing the detrimental effects of Joule heating even at high voltages. The resolution of microscale free flow electrophoresis, however, is limited by the broadening of the analyte beam in the microfluidic channel, an effect that becomes especially pronounced when the analyte is deflected significantly away from its original position. Here, we describe and demonstrate how restricting spatially the sample injection and collection to the regions where the gradients in the velocity distribution of the carrier medium are the smallest allows this broadening effect to be substantially suppressed and hence the resolution of microscale free flow electrophoresis devices to be increased. To demonstrate this concept, we fabricated microfluidic free flow electrophoresis devices with spatially restricted injection nozzles implemented through the use of multilayer soft-photolithography and further integrated quartz based observation areas for fluorescent detection and imaging. With these devices, we demonstrated a 5-fold reduction in the extent of beam broadening relative to conventional free flow electrophoresis approaches with nonrestricted sample introduction. The manifold enhancement in the achievable resolution of microscale free flow electrophoresis devices opens up the possibility of rapid separation and analysis of complex mixtures.

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Section: Optical Detection In the Deep Uv-wavelength Regionmentioning

confidence: 66%

Enhancing the Resolution of Micro Free Flow Electrophoresis through Spatially Controlled Sample Injection

Saar

Müller²,

Charmet

et al. 2018

Anal. Chem.

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“…A thin sample stream is introduced into a planar separation channel with a buffer running in parallel: when the electric field is applied perpendicularly across the separation chamber, charged analytes deflect laterally based on their electrophoretic mobility. When operating at the microscale, thus acquiring several well-known advantages related to the scaling down of the dimensions, the microfluidic approach allows for the implementation of correspondingly scaled micro free-flow electrophoresis (µFFE) [24]. Except for the first µFFE devices, which were manufactured in silicon through a standard lithographic process [25], nowadays the majority of the µFFE devices are developed by exploiting various types of polymers through soft-lithographic or replica molding strategies [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Application of a Micro Free-Flow Electrophoresis 3D Printed Lab-on-a-Chip for Micro-Nanoparticles Analysis

2020

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The present work describes a novel microfluidic free-flow electrophoresis device developed by applying three-dimensional (3D) printing technology to rapid prototype a low-cost chip for micro- and nanoparticle collection and analysis. Accurate reproducibility of the device design and the integration of the inlet and outlet ports with the proper tube interconnection was achieved by the additive manufacturing process. Test prints were performed to compare the glossy and the matte type of surface finish. Analyzing the surface topography of the 3D printed device, we demonstrated how the best reproducibility was obtained with the glossy device showing a 5% accuracy. The performance of the device was demonstrated by a free-flow zone electrophoresis application on micro- and nanoparticles with different dimensions, charge surfaces and fluorescent dyes by applying different separation voltages up to 55 V. Dynamic light scattering (DLS) measurements and ultraviolet−visible spectroscopy (UV−Vis) analysis were performed on particles collected at the outlets. The percentage of particles observed at each outlet was determined in order to demonstrate the capability of the micro free-flow electrophoresis (µFFE) device to work properly in dependence of the applied electric field. In conclusion, we rapid prototyped a microfluidic device by 3D printing, which ensured micro- and nanoparticle deviation and concentration in a reduced operation volume and hence suitable for biomedical as well as pharmaceutical applications.

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“…Recently, LLE based on the free‐flow zone electrophoresis (FFZE) technique has been proposed as a promising sample clean‐up method for ESI‐MS analysis due to its easy inline integration and applicability to a wide variety of analytes ranging from proteins to endoplasmic reticulum membranes [24‐26]. In addition, miniaturization of FFZE methods on the microchip format can further allow significant savings in sample consumption and separation time [27‐30] besides rendering them readily integrable to other analytical procedures, for example, capillary zone electrophoresis [31] and sample preconcentration [32]. More recently, microchip‐based FFZE assays have been integrated to ESI‐MS systems by our research group [33] as well as others [34] allowing label‐free characterization of target analytes with high sensitivity.…”

Section: Introductionmentioning

confidence: 99%

Enhancement in MS‐based peptide detection by microfluidic free‐flow zone electrophoresis

2020

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Enhancement in MS-based peptide detection by microfluidic free-flow zone electrophoresisMatrix components are known to significantly alter the ionization of a target analyte in ESIbased measurements particularly when working with complex biological samples. This issue however may be alleviated by extracting the analyte of interest from the original sample into a relatively simple matrix compatible with ESI mass-spectrometric analysis. In this article, we report a microfluidic device that enables such extraction of small peptide molecules into an ESI-compatible solvent stream significantly improving both the sensitivity and reproducibility of the measurements. The reported device realizes this analyte extraction capability based on the free-flow zone electrophoretic fractionation process using a set of internal electrodes placed across the width of the analysis channel. Employing lateral electric fields and separation distances of 75 V/cm and 600 µm, respectively, efficient extraction of the model peptide human angiotensin II was demonstrated allowing a reduction in its detection limit by one to three orders of magnitude using the ESI-MS method. The noted result was obtained in our experiments both for a relatively simple specimen comprising DNA strands and angiotensin II as well as for human serum samples spiked with the same model peptide. Abbreviations: FFZE, free-flow zone electrophoresis; LLE, liquid-liquid extraction Color online: See article online to view Fig. 1-5 in color.

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Micro free flow electrophoresis

Cited by 50 publications

References 83 publications

Enhancing the Resolution of Micro Free Flow Electrophoresis through Spatially Controlled Sample Injection

Enhancing the Resolution of Micro Free Flow Electrophoresis through Spatially Controlled Sample Injection

Application of a Micro Free-Flow Electrophoresis 3D Printed Lab-on-a-Chip for Micro-Nanoparticles Analysis

Enhancement in MS‐based peptide detection by microfluidic free‐flow zone electrophoresis

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