1
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Barekatain M, Liu Y, Archambeau A, Cherezov V, Fraser S, White KL, Hayes MA. Insulator-based dielectrophoresis-assisted separation of insulin secretory vesicles. eLife 2024; 13:e74989. [PMID: 39190030 PMCID: PMC11349295 DOI: 10.7554/elife.74989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 07/24/2024] [Indexed: 08/28/2024] Open
Abstract
Organelle heterogeneity and inter-organelle contacts within a single cell contribute to the limited sensitivity of current organelle separation techniques, thus hindering organelle subpopulation characterization. Here, we use direct current insulator-based dielectrophoresis (DC-iDEP) as an unbiased separation method and demonstrate its capability by identifying distinct distribution patterns of insulin vesicles from INS-1E insulinoma cells. A multiple voltage DC-iDEP strategy with increased range and sensitivity has been applied, and a differentiation factor (ratio of electrokinetic to dielectrophoretic mobility) has been used to characterize features of insulin vesicle distribution patterns. We observed a significant difference in the distribution pattern of insulin vesicles isolated from glucose-stimulated cells relative to unstimulated cells, in accordance with maturation of vesicles upon glucose stimulation. We interpret the difference in distribution pattern to be indicative of high-resolution separation of vesicle subpopulations. DC-iDEP provides a path for future characterization of subtle biochemical differences of organelle subpopulations within any biological system.
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Affiliation(s)
- Mahta Barekatain
- Department of Chemistry, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern CaliforniaLos AngelesUnited States
| | - Yameng Liu
- School of Molecular Sciences, Arizona State UniversityTempeUnited States
| | - Ashley Archambeau
- Department of Chemistry, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern CaliforniaLos AngelesUnited States
| | - Vadim Cherezov
- Department of Chemistry, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern CaliforniaLos AngelesUnited States
| | - Scott Fraser
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern CaliforniaLos AngelesUnited States
| | - Kate L White
- Department of Chemistry, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern CaliforniaLos AngelesUnited States
| | - Mark A Hayes
- School of Molecular Sciences, Arizona State UniversityTempeUnited States
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2
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Lapizco-Encinas BH. Nonlinear Electrokinetic Methods of Particles and Cells. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2024; 17:243-264. [PMID: 38360552 DOI: 10.1146/annurev-anchem-061622-040810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Nonlinear electrokinetic phenomena offer label-free, portable, and robust approaches for particle and cell assessment, including selective enrichment, separation, sorting, and characterization. The field of electrokinetics has evolved substantially since the first separation reports by Arne Tiselius in the 1930s. The last century witnessed major advances in the understanding of the weak-field theory, which supported developments in the use of linear electrophoresis and its adoption as a routine analytical technique. More recently, an improved understanding of the strong-field theory enabled the development of nonlinear electrokinetic techniques such as electrorotation, dielectrophoresis, and nonlinear electrophoresis. This review discusses the operating principles and recent applications of these three nonlinear electrokinetic phenomena for the analysis and manipulation of particles and cells and provides an overview of some of the latest developments in the field of nonlinear electrokinetics.
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Affiliation(s)
- Blanca H Lapizco-Encinas
- Microscale Bioseparations Laboratory and Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, New York, USA;
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3
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Nasir Ahamed NN, Mendiola-Escobedo CA, Perez-Gonzalez VH, Lapizco-Encinas BH. Development of a DC-Biased AC-Stimulated Microfluidic Device for the Electrokinetic Separation of Bacterial and Yeast Cells. BIOSENSORS 2024; 14:237. [PMID: 38785711 PMCID: PMC11117482 DOI: 10.3390/bios14050237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 04/19/2024] [Accepted: 05/04/2024] [Indexed: 05/25/2024]
Abstract
Electrokinetic (EK) microsystems, which are capable of performing separations without the need for labeling analytes, are a rapidly growing area in microfluidics. The present work demonstrated three distinct binary microbial separations, computationally modeled and experimentally performed, in an insulator-based EK (iEK) system stimulated by DC-biased AC potentials. The separations had an increasing order of difficulty. First, a separation between cells of two distinct domains (Escherichia coli and Saccharomyces cerevisiae) was demonstrated. The second separation was for cells from the same domain but different species (Bacillus subtilis and Bacillus cereus). The last separation included cells from two closely related microbial strains of the same domain and the same species (two distinct S. cerevisiae strains). For each separation, a novel computational model, employing a continuous spatial and temporal function for predicting the particle velocity, was used to predict the retention time (tR,p) of each cell type, which aided the experimentation. All three cases resulted in separation resolution values Rs>1.5, indicating complete separation between the two cell species, with good reproducibility between the experimental repetitions (deviations < 6%) and good agreement (deviations < 18%) between the predicted tR,p and experimental (tR,e) retention time values. This study demonstrated the potential of DC-biased AC iEK systems for performing challenging microbial separations.
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Affiliation(s)
- Nuzhet Nihaar Nasir Ahamed
- Microscale Bioseparations Laboratory, Biomedical Engineering Department, Rochester Institute of Technology, 160 Lomb Memorial Drive, Rochester, NY 14623, USA; (N.N.N.A.); (C.A.M.-E.)
| | - Carlos A. Mendiola-Escobedo
- Microscale Bioseparations Laboratory, Biomedical Engineering Department, Rochester Institute of Technology, 160 Lomb Memorial Drive, Rochester, NY 14623, USA; (N.N.N.A.); (C.A.M.-E.)
- School of Engineering and Sciences, Tecnologico de Monterrey, Monterrey 64700, Nuevo Leon, Mexico
| | - Victor H. Perez-Gonzalez
- School of Engineering and Sciences, Tecnologico de Monterrey, Monterrey 64700, Nuevo Leon, Mexico
| | - Blanca H. Lapizco-Encinas
- Microscale Bioseparations Laboratory, Biomedical Engineering Department, Rochester Institute of Technology, 160 Lomb Memorial Drive, Rochester, NY 14623, USA; (N.N.N.A.); (C.A.M.-E.)
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4
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Nasir Ahamed NN, Mendiola-Escobedo CA, Perez-Gonzalez VH, Lapizco-Encinas BH. Assessing the Discriminatory Capabilities of iEK Devices under DC and DC-Biased AC Stimulation Potentials. MICROMACHINES 2023; 14:2239. [PMID: 38138408 PMCID: PMC10745336 DOI: 10.3390/mi14122239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 12/09/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023]
Abstract
There is a rising need for rapid and reliable analytical methods for separating microorganisms in clinical and biomedical applications. Microscale-insulator-based electrokinetic (iEK) systems have proven to be robust platforms for assessing a wide variety of microorganisms. Traditionally, iEK systems are usually stimulated with direct-current (DC) potentials. This work presents a comparison between using DC potentials and using DC-biased alternating-current (AC) potentials in iEK systems for the separation of microorganisms. The present study, which includes mathematical modeling and experimentation, compares the separation of bacterial and yeast cells in two distinct modes by using DC and DC-biased AC potentials. The quality of both separations, assessed in terms of separation resolution (Rs), showed a complete separation (Rs = 1.51) with the application of a DC-biased low-frequency AC signal but an incomplete separation (Rs = 0.55) with the application of an RMS-equivalent DC signal. Good reproducibility between experimental repetitions (<10%) was obtained, and good agreement (~18% deviation) was observed between modeling and experimental retention times. The present study demonstrates the potential of extending the limits of iEK systems by employing DC-biased AC potentials to perform discriminatory separations of microorganisms that are difficult to separate with the application of DC potentials.
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Affiliation(s)
- Nuzhet Nihaar Nasir Ahamed
- Microscale Bioseparations Laboratory, Biomedical Engineering Department, Rochester Institute of Technology, 160 Lomb Memorial Drive, Rochester, NY 14623, USA;
| | | | | | - Blanca H. Lapizco-Encinas
- Microscale Bioseparations Laboratory, Biomedical Engineering Department, Rochester Institute of Technology, 160 Lomb Memorial Drive, Rochester, NY 14623, USA;
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5
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Koh D, Sonker M, Arriaga EA, Ros A. Numerical modeling reveals improved organelle separation for dielectrophoretic ratchet migration. Electrophoresis 2023; 44:1826-1836. [PMID: 37622551 PMCID: PMC10905386 DOI: 10.1002/elps.202300091] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 08/01/2023] [Accepted: 08/07/2023] [Indexed: 08/26/2023]
Abstract
Organelle size varies with normal and abnormal cell function. Thus, size-based particle separation techniques are key to assessing the properties of organelle subpopulations differing in size. Recently, insulator-based dielectrophoresis (iDEP) has gained significant interest as a technique to manipulate sub-micrometer-sized particles enabling the assessment of organelle subpopulations. Based on iDEP, we recently reported a ratchet device that successfully demonstrated size-based particle fractionation in combination with continuous flow sample injection. Here, we used a numerical model to optimize the performance with flow rates a factor of three higher than previously and increased the channel volume to improve throughput. We evaluated the amplitude and duration of applied low-frequency DC-biased AC potentials improving separation efficiency. A separation efficiency of nearly 0.99 was achieved with the optimization of key parameters-improved from 0.80 in previous studies (Ortiz et al. Electrophoresis, 2022;43;1283-1296)-demonstrating that fine-tuning the periodical driving forces initiating the ratchet migration under continuous flow conditions can significantly improve the fractionation of organelles of different sizes.
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Affiliation(s)
- Domin Koh
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Mukul Sonker
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Edgar A Arriaga
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Alexandra Ros
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, Arizona, USA
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6
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Moore JH, Salahi A, Honrado C, Warburton C, Tate S, Warren CA, Swami NS. Correlating Antibiotic-Induced Dysbiosis to Clostridioides difficile Spore Germination and Host Susceptibility to Infection Using an Ex Vivo Assay. ACS Infect Dis 2023; 9:1878-1888. [PMID: 37756389 PMCID: PMC10581205 DOI: 10.1021/acsinfecdis.3c00192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Indexed: 09/29/2023]
Abstract
Antibiotic-induced microbiota disruption and its persistence create conditions for dysbiosis and colonization by opportunistic pathogens, such as those causing Clostridioides difficile (C. difficile) infection (CDI), which is the most severe hospital-acquired intestinal infection. Given the wide differences in microbiota across hosts and in their recovery after antibiotic treatments, there is a need for assays to assess the influence of dysbiosis and its recovery dynamics on the susceptibility of the host to CDI. Germination of C. difficile spores is a key virulence trait for the onset of CDI, which is influenced by the level of primary vs secondary bile acids in the intestinal milieu that is regulated by the microbiota composition. Herein, the germination of C. difficile spores in fecal supernatant from mice that are subject to varying degrees of antibiotic treatment is utilized as an ex vivo assay to predict intestinal dysbiosis in the host based on their susceptibility to CDI, as determined by in vivo CDI metrics in the same mouse model. Quantification of spore germination down to lower detection limits than the colony-forming assay is achieved by using impedance cytometry to count single vegetative bacteria that are identified based on their characteristic electrical physiology for distinction vs aggregated spores and cell debris in the media. As a result, germination can be quantified at earlier time points and with fewer spores for correlation to CDI outcomes. This sets the groundwork for a point-of-care tool to gauge the susceptibility of human microbiota to CDI after antibiotic treatments.
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Affiliation(s)
- John H. Moore
- Electrical
and Computer Engineering, University of
Virginia, Charlottesville, Virginia 22904, United States
| | - Armita Salahi
- Electrical
and Computer Engineering, University of
Virginia, Charlottesville, Virginia 22904, United States
| | - Carlos Honrado
- Electrical
and Computer Engineering, University of
Virginia, Charlottesville, Virginia 22904, United States
| | - Christopher Warburton
- Electrical
and Computer Engineering, University of
Virginia, Charlottesville, Virginia 22904, United States
| | - Steven Tate
- Electrical
and Computer Engineering, University of
Virginia, Charlottesville, Virginia 22904, United States
| | - Cirle A. Warren
- Infectious
Diseases, School of Medicine, University
of Virginia, Charlottesville, Virginia 22903, United States
| | - Nathan S. Swami
- Electrical
and Computer Engineering, University of
Virginia, Charlottesville, Virginia 22904, United States
- Chemistry, University
of Virginia, Charlottesville, Virginia 22904, United States
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7
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Vaghef-Koodehi A, Ernst OD, Lapizco-Encinas BH. Separation of Cells and Microparticles in Insulator-Based Electrokinetic Systems. Anal Chem 2023; 95:1409-1418. [PMID: 36599093 DOI: 10.1021/acs.analchem.2c04366] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Presented here is the first continuous separation of microparticles and cells of similar characteristics employing linear and nonlinear electrokinetic phenomena in an insulator-based electrokinetic (iEK) system. By utilizing devices with insulating features, which distort the electric field distribution, it is possible to combine linear and nonlinear EK phenomena, resulting in highly effective separation schemes that leverage the new advancements in nonlinear electrophoresis. This work combines mathematical modeling and experimentation to separate four distinct binary mixtures of particles and cells. A computational model with COMSOL Multiphysics was used to predict the retention times (tR,p) of the particles and cells in iEK devices. Then, the experimental separations were carried out using the conditions identified with the model, where the experimental retention time (tR,e) of the particles and cells was measured. A total of four distinct separations of binary mixtures were performed by increasing the level of difficulty. For the first separation, two types of polystyrene microparticles, selected to mimic Escherichia coli and Saccharomyces cerevisiae cells, were separated. By leveraging the knowledge gathered from the first separation, a mixture of cells of distinct domains and significant size differences, E. coli and S. cerevisiae, was successfully separated. The third separation also featured cells of different domains but closer in size: Bacillus cereus versus S. cerevisiae. The last separation included cells in the same domain and genus, B. cereus versus Bacillus subtilis. Separation results were evaluated in terms of number of plates (N) and separation resolution (Rs), where Rs values for all separations were above 1.5, illustrating complete separations. Experimental results were in agreement with modeling results in terms of retention times, with deviations in the 6-27% range, while the variation between repetitions was between 2 and 18%, demonstrating good reproducibility. This report is the first prediction of the retention time of cells in iEK systems.
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Affiliation(s)
- Alaleh Vaghef-Koodehi
- Microscale Bioseparations Laboratory and Biomedical Engineering Department, Rochester Institute of Technology, 160 Lomb Memorial Drive, Rochester, New York14623, United States
| | - Olivia D Ernst
- Microscale Bioseparations Laboratory and Biomedical Engineering Department, Rochester Institute of Technology, 160 Lomb Memorial Drive, Rochester, New York14623, United States
| | - Blanca H Lapizco-Encinas
- Microscale Bioseparations Laboratory and Biomedical Engineering Department, Rochester Institute of Technology, 160 Lomb Memorial Drive, Rochester, New York14623, United States
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8
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Huang X, Torres‐Castro K, Varhue W, Rane A, Rasin A, Swami NS. On‐chip microfluidic buffer swap of biological samples in‐line with downstream dielectrophoresis. Electrophoresis 2022; 43:1275-1282. [PMID: 35286736 PMCID: PMC9203925 DOI: 10.1002/elps.202100304] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 12/12/2021] [Accepted: 01/24/2022] [Indexed: 11/08/2022]
Abstract
Microfluidic cell enrichment by dielectrophoresis, based on biophysical and electrophysiology phenotypes, requires that cells be resuspended from their physiological media into a lower conductivity buffer for enhancing force fields and enabling the dielectric contrast needed for separation. To ensure that sensitive cells are not subject to centrifugation for resuspension and spend minimal time outside of their culture media, we present an on‐chip microfluidic strategy for swapping cells into media tailored for dielectrophoresis. This strategy transfers cells from physiological media into a 100‐fold lower conductivity media by using tangential flows of low media conductivity at 200‐fold higher flow rate versus sample flow to promote ion diffusion over the length of a straight channel architecture that maintains laminarity of the flow‐focused sample and minimizes cell dispersion across streamlines. Serpentine channels are used downstream from the flow‐focusing region to modulate hydrodynamic resistance of the central sample outlet versus flanking outlets that remove excess buffer, so that cell streamlines are collected in the exchanged buffer with minimal dilution in cell numbers and at flow rates that support dielectrophoresis. We envision integration of this on‐chip sample preparation platform prior to or post‐dielectrophoresis, in‐line with on‐chip monitoring of the outlet sample for metrics of media conductivity, cell velocity, cell viability, cell position, and collected cell numbers, so that the cell flow rate and streamlines can be tailored for enabling dielectrophoretic separations from heterogeneous samples.
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Affiliation(s)
- Xuhai Huang
- Electrical and Computer Engineering University of Virginia Charlottesville Virginia USA
| | - Karina Torres‐Castro
- Electrical and Computer Engineering University of Virginia Charlottesville Virginia USA
| | - Walter Varhue
- Electrical and Computer Engineering University of Virginia Charlottesville Virginia USA
| | - Aditya Rane
- Department of Chemistry University of Virginia Charlottesville Virginia USA
| | - Ahmed Rasin
- Electrical and Computer Engineering University of Virginia Charlottesville Virginia USA
| | - Nathan S. Swami
- Electrical and Computer Engineering University of Virginia Charlottesville Virginia USA
- Department of Chemistry University of Virginia Charlottesville Virginia USA
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9
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Ortiz R, Koh D, Kim DH, Rabbani MT, Anguaya Velasquez C, Sonker M, Arriaga EA, Ros A. Continuous organelle separation in an insulator-based dielectrophoretic device. Electrophoresis 2022; 43:1283-1296. [PMID: 34964147 PMCID: PMC10905415 DOI: 10.1002/elps.202100326] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/30/2021] [Accepted: 12/13/2021] [Indexed: 11/06/2022]
Abstract
Heterogeneity in organelle size has been associated with devastating human maladies such as neurodegenerative diseases or cancer. Therefore, assessing the size-based subpopulation of organelles is imperative to understand the biomolecular foundations of these diseases. Here, we demonstrated a ratchet migration mechanism using insulator-based dielectrophoresis in conjunction with a continuous flow component that allows the size-based separation of submicrometer particles. The ratchet mechanism was realized in a microfluidic device exhibiting an array of insulating posts, tailoring electrokinetic and dielectrophoretic transport. A numerical model was developed to elucidate the particle migration and the size-based separation in various conditions. Experimentally, the size-based separation of a mixture of polystyrene beads (0.28 and 0.87 μ $\umu $ m) was accomplished demonstrating good agreement with the numerical model. Furthermore, the size-based separation of mitochondria was investigated using a mitochondria mixture isolated from HepG2 cells and HepG2 cells carrying the gene Mfn-1 knocked out, indicating distinct size-related migration behavior. With the presented continuous flow separation device, larger amounts of fractionated organelles can be collected in the future allowing access to the biomolecular signature of mitochondria subpopulations differing in size.
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Affiliation(s)
- Ricardo Ortiz
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Domin Koh
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Dai Hyun Kim
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Mohammad Towshif Rabbani
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Cesar Anguaya Velasquez
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Mukul Sonker
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Edgar A Arriaga
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Alexandra Ros
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, USA
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10
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Vaghef-Koodehi A, Dillis C, Lapizco-Encinas BH. High-Resolution Charge-Based Electrokinetic Separation of Almost Identical Microparticles. Anal Chem 2022; 94:6451-6456. [PMID: 35441512 DOI: 10.1021/acs.analchem.2c00355] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Well-established techniques, e.g., chromatography and capillary electrophoresis, are available for separating nanosized particles, such as proteins. However, similar techniques for separating micron-sized particles are still needed. Insulator-based electrokinetic (iEK) systems can achieve efficient microparticle separations by combining linear and nonlinear EK phenomena. Of particular interest are charge-based separations, which could be employed for separating similar microorganisms, such as bacterial cells of the same size, same genus, or same strain. Several groups have reported charge-based separations of microparticles where a zeta potential difference of at least 40 mV between the microparticles was required. The present work pushes the limit of the discriminatory capabilities of iEK systems by reporting the charged-based separation of two microparticles of the same size (5.1 μm), same shape, same substrate material, and with a small difference in particle zeta potentials of only 3.6 mV, which is less than 10% of the difference in previous studies. By building an accurate COMSOL Multiphysics model, which correctly accounts for dielectrophoresis and electrophoresis of the second kind, it was possible to identify the conditions to achieve this challenging separation. Furthermore, the COMSOL model allowed predicting particle retention times (tR,p) which were compared with experimental values (tR,e). The separations results had excellent reproducibility in terms of tR,e with variations of only 9% and 11% between repetitions. These findings demonstrate that, by following a robust protocol that involves modeling and experimental work, it is possible to discriminate between highly similar particles, with much smaller differences in electrical charge than previously reported.
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Affiliation(s)
- Alaleh Vaghef-Koodehi
- Microscale Bioseparations Laboratory and Biomedical Engineering Department, Rochester Institute of Technology, 160 Lomb Memorial Drive, Rochester, New York 14623, United States
| | - Curran Dillis
- Microscale Bioseparations Laboratory and Biomedical Engineering Department, Rochester Institute of Technology, 160 Lomb Memorial Drive, Rochester, New York 14623, United States
| | - Blanca H Lapizco-Encinas
- Microscale Bioseparations Laboratory and Biomedical Engineering Department, Rochester Institute of Technology, 160 Lomb Memorial Drive, Rochester, New York 14623, United States
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11
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Salahi A, Honrado C, Rane A, Caselli F, Swami NS. Modified Red Blood Cells as Multimodal Standards for Benchmarking Single-Cell Cytometry and Separation Based on Electrical Physiology. Anal Chem 2022; 94:2865-2872. [PMID: 35107262 PMCID: PMC8852356 DOI: 10.1021/acs.analchem.1c04739] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 01/18/2022] [Indexed: 02/04/2023]
Abstract
Biophysical cellular information at single-cell sensitivity is becoming increasingly important within analytical and separation platforms that associate the cell phenotype with markers of disease, infection, and immunity. Frequency-modulated electrically driven microfluidic measurement and separation systems offer the ability to sensitively identify single cells based on biophysical information, such as their size and shape, as well as their subcellular membrane morphology and cytoplasmic organization. However, there is a lack of reliable and reproducible model particles with well-tuned subcellular electrical phenotypes that can be used as standards to benchmark the electrical physiology of unknown cell types or to benchmark dielectrophoretic separation metrics of novel device strategies. Herein, the application of red blood cells (RBCs) as multimodal standard particles with systematically modulated subcellular electrophysiology and associated fluorescence level is presented. Using glutaraldehyde fixation to vary membrane capacitance and by membrane resealing after electrolyte penetration to vary interior cytoplasmic conductivity and fluorescence in a correlated manner, each modified RBC type can be identified at single-cell sensitivity based on phenomenological impedance metrics and fitted to dielectric models to compute biophysical information. In this manner, single-cell impedance data from unknown RBC types can be mapped versus these model RBC types for facile determination of subcellular biophysical information and their dielectrophoretic separation conditions, without the need for time-consuming algorithms that often require unknown fitting parameters. Such internal standards for biophysical cytometry can advance in-line phenotypic recognition strategies.
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Affiliation(s)
- Armita Salahi
- Electrical
and Computer Engineering, University of
Virginia, Charlottesville, Virginia 22904, United States
| | - Carlos Honrado
- Electrical
and Computer Engineering, University of
Virginia, Charlottesville, Virginia 22904, United States
| | - Aditya Rane
- Chemistry, University
of Virginia, Charlottesville, Virginia 22904, United States
| | - Federica Caselli
- Civil
Engineering and Computer Science, University
of Rome Tor Vergata, 00133 Rome, Italy
| | - Nathan S. Swami
- Electrical
and Computer Engineering, University of
Virginia, Charlottesville, Virginia 22904, United States
- Chemistry, University
of Virginia, Charlottesville, Virginia 22904, United States
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12
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Maidin NNM, Buyong MR, Rahim RA, Mohamed MA. Dielectrophoresis applications in biomedical field and future perspectives in biomedical technology. Electrophoresis 2021; 42:2033-2059. [PMID: 34346062 DOI: 10.1002/elps.202100043] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 07/25/2021] [Accepted: 07/27/2021] [Indexed: 11/09/2022]
Abstract
Dielectrophoresis (DEP) is a technique to manipulate trajectories of polarisable particles in non-uniform electric fields by utilising unique dielectric properties. The manipulation of a cell using DEP has been demonstrated in various modes, thereby indicating potential applications in the biomedical field. In this review, recent DEP applications in the biomedical field are discussed. This review is intended to highlight research work that shows significant approach related to dielectrophoresis application in biomedical field reported between 2016 and 2020. Firstly, single-shell model and multiple-shell model of cells are introduced. Current device structures and recently introduced electrode patterns for DEP applications are discussed. Secondly, the biomedical uses of DEP in liquid biopsies, stem cell therapies, and diagnosis of infectious diseases due to bacteria and viruses are presented. Finally, the challenges in DEP research are discussed, and the reported solutions are explained. DEP's potential research directions are mentioned. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Nur Nasyifa Mohd Maidin
- Institute of Microengineering and Nanoelectronic (IMEN), Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor, 43600, Malaysia
| | - Muhamad Ramdzan Buyong
- Institute of Microengineering and Nanoelectronic (IMEN), Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor, 43600, Malaysia
| | - Ruslinda A Rahim
- Institute of Nano Electronic Engineering (INEE), Universiti Malaysia Perlis (UniMAP), Kangar, Perlis, 01000, Malaysia.,National Nanotechnology Centre (NNC), Ministry of Science Technology and Innovation (MOSTI), Federal Government Administrative Centre, Putrajaya, 62662, Malaysia
| | - Mohd Ambri Mohamed
- Institute of Microengineering and Nanoelectronic (IMEN), Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor, 43600, Malaysia
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