1
|
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.
Collapse
Affiliation(s)
- Blanca H Lapizco-Encinas
- Microscale Bioseparations Laboratory and Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, New York, USA;
| |
Collapse
|
2
|
Ajala S, Muraleedharan Jalajamony H, Nair M, Marimuthu P, Fernandez RE. Comparing machine learning and deep learning regression frameworks for accurate prediction of dielectrophoretic force. Sci Rep 2022; 12:11971. [PMID: 35831342 PMCID: PMC9279499 DOI: 10.1038/s41598-022-16114-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 07/05/2022] [Indexed: 11/09/2022] Open
Abstract
An intelligent sensing framework using Machine Learning (ML) and Deep Learning (DL) architectures to precisely quantify dielectrophoretic force invoked on microparticles in a textile electrode-based DEP sensing device is reported. The prediction accuracy and generalization ability of the framework was validated using experimental results. Images of pearl chain alignment at varying input voltages were used to build deep regression models using modified ML and CNN architectures that can correlate pearl chain alignment patterns of Saccharomyces cerevisiae(yeast) cells and polystyrene microbeads to DEP force. Various ML models such as K-Nearest Neighbor, Support Vector Machine, Random Forest, Neural Networks, and Linear Regression along with DL models such as Convolutional Neural Network (CNN) architectures of AlexNet, ResNet-50, MobileNetV2, and GoogLeNet have been analyzed in order to build an effective regression framework to estimate the force induced on yeast cells and microbeads. The efficiencies of the models were evaluated using Mean Absolute Error, Mean Absolute Relative, Mean Squared Error, R-squared, and Root Mean Square Error (RMSE) as evaluation metrics. ResNet-50 with RMSPROP gave the best performance, with a validation RMSE of 0.0918 on yeast cells while AlexNet with ADAM optimizer gave the best performance, with a validation RMSE of 0.1745 on microbeads. This provides a baseline for further studies in the application of deep learning in DEP aided Lab-on-Chip devices.
Collapse
Affiliation(s)
- Sunday Ajala
- Department of Engineering, Norfolk State University, Norfolk, USA
| | | | - Midhun Nair
- APJ Abdul Kalam Technological University, Thiruvananthapuram, India
| | - Pradeep Marimuthu
- Rajeev Gandhi College of Engineering and Technology, Puducherry, India
| | | |
Collapse
|
3
|
Deep-Learning Based Estimation of Dielectrophoretic Force. MICROMACHINES 2021; 13:mi13010041. [PMID: 35056207 PMCID: PMC8779967 DOI: 10.3390/mi13010041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 12/24/2021] [Accepted: 12/26/2021] [Indexed: 11/22/2022]
Abstract
The ability to accurately quantify dielectrophoretic (DEP) force is critical in the development of high-efficiency microfluidic systems. This is the first reported work that combines a textile electrode-based DEP sensing system with deep learning in order to estimate the DEP forces invoked on microparticles. We demonstrate how our deep learning model can process micrographs of pearl chains of polystyrene (PS) microbeads to estimate the DEP forces experienced. Numerous images obtained from our experiments at varying input voltages were preprocessed and used to train three deep convolutional neural networks, namely AlexNet, MobileNetV2, and VGG19. The performances of all the models was tested for their validation accuracies. Models were also tested with adversarial images to evaluate performance in terms of classification accuracy and resilience as a result of noise, image blur, and contrast changes. The results indicated that our method is robust under unfavorable real-world settings, demonstrating that it can be used for the direct estimation of dielectrophoretic force in point-of-care settings.
Collapse
|
4
|
Vaghef-Koodehi A, Lapizco-Encinas BH. Microscale electrokinetic-based analysis of intact cells and viruses. Electrophoresis 2021; 43:263-287. [PMID: 34796523 DOI: 10.1002/elps.202100254] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/08/2021] [Accepted: 11/11/2021] [Indexed: 12/11/2022]
Abstract
Miniaturized electrokinetic methods have proven to be robust platforms for the analysis and assessment of intact microorganisms, offering short response times and higher integration than their bench-scale counterparts. The present review article discusses three types of electrokinetic-based methodologies: electromigration or motion-based techniques, electrode-based electrokinetics, and insulator-based electrokinetics. The fundamentals of each type of methodology are discussed and relevant examples from recent reports are examined, to provide the reader with an overview of the state-of-the-art on the latest advancements on the analysis of intact cells and viruses with microscale electrokinetic techniques. The concluding remarks discuss the potential applications and future directions.
Collapse
Affiliation(s)
- Alaleh Vaghef-Koodehi
- Microscale Bioseparations Laboratory and Biomedical Engineering Department, Rochester Institute of Technology, Rochester, NY, USA
| | - Blanca H Lapizco-Encinas
- Microscale Bioseparations Laboratory and Biomedical Engineering Department, Rochester Institute of Technology, Rochester, NY, USA
| |
Collapse
|
5
|
Fernández-Mateo R, Calero V, Morgan H, Ramos A, García-Sánchez P. Concentration-Polarization Electroosmosis near Insulating Constrictions within Microfluidic Channels. Anal Chem 2021; 93:14667-14674. [PMID: 34704741 PMCID: PMC8581963 DOI: 10.1021/acs.analchem.1c02849] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Electric fields are
commonly used to trap and separate micro- and
nanoparticles near channel constrictions in microfluidic devices.
The trapping mechanism is attributed to the electrical forces arising
from the nonhomogeneous electric field caused by the constrictions,
and the phenomenon is known as insulator-based-dielectrophoresis (iDEP).
In this paper, we describe stationary electroosmotic flows of electrolytes
around insulating constrictions induced by low frequency AC electric
fields (below 10 kHz). Experimental characterization of the flows
is described for two different channel heights (50 and 10 μm),
together with numerical simulations based on an electrokinetic model
that considers the modification of the local ionic concentration due
to surface conductance on charged insulating walls. We term this phenomenon
concentration–polarization electroosmosis (CPEO). The observed
flow characteristics are in qualitative agreement with the predictions
of this model. However, for shallow channels (10 μm),
trapping of the particles on both sides of the constrictions is also
observed. This particle and fluid behavior could play a major role
in iDEP and could be easily misinterpreted as a dielectrophoretic
force.
Collapse
Affiliation(s)
- Raúl Fernández-Mateo
- School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Víctor Calero
- Departamento de Electrónica y Electromagnetismo, Facultad de Física, Universidad de Sevilla, Avda. Reina Mercedes s/n, 41012 Sevilla, Spain
| | - Hywel Morgan
- School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Antonio Ramos
- Departamento de Electrónica y Electromagnetismo, Facultad de Física, Universidad de Sevilla, Avda. Reina Mercedes s/n, 41012 Sevilla, Spain
| | - Pablo García-Sánchez
- Departamento de Electrónica y Electromagnetismo, Facultad de Física, Universidad de Sevilla, Avda. Reina Mercedes s/n, 41012 Sevilla, Spain
| |
Collapse
|
6
|
Hakim KS, Lapizco-Encinas BH. Analysis of microorganisms with nonlinear electrokinetic microsystems. Electrophoresis 2021; 42:588-604. [PMID: 33151541 DOI: 10.1002/elps.202000233] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/04/2020] [Accepted: 11/02/2020] [Indexed: 02/06/2023]
Abstract
Nonlinear electrokinetics (EK), specifically electrophoresis of the second kind, dielectrophoresis (DEP) and electrorotation (EROT), have gained significant interest recently for their flexibility and labeless discriminant manner of operation. The current applications of these technologies are a clear advancement from what they were when first discovered, but also still show strong signs of future growth. The present review article presents a discussion of the current uses of microscale nonlinear EK technologies as analytical, sensing, and purification tools for microorganisms. The discussion is focused on some of the latest discoveries with various nonlinear EK microfluidic techniques, such as DEP particle trapping and EROT for particle assessments, for the analysis of microorganisms ranging from viruses to parasites. Along the way, special focus was given to key research articles from within the past two years to provide the most up-to-date knowledge on the current state-of-the-art within the field of microscale EK, and from there, an outlook on where the future of the field is headed is also included.
Collapse
Affiliation(s)
- Kel S Hakim
- Microscale Bioseparations Laboratory and Biomedical Engineering Department, Rochester Institute of Technology, Rochester, NY, USA
| | - Blanca H Lapizco-Encinas
- Microscale Bioseparations Laboratory and Biomedical Engineering Department, Rochester Institute of Technology, Rochester, NY, USA
| |
Collapse
|
7
|
Honrado C, Bisegna P, Swami NS, Caselli F. Single-cell microfluidic impedance cytometry: from raw signals to cell phenotypes using data analytics. LAB ON A CHIP 2021; 21:22-54. [PMID: 33331376 PMCID: PMC7909465 DOI: 10.1039/d0lc00840k] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The biophysical analysis of single-cells by microfluidic impedance cytometry is emerging as a label-free and high-throughput means to stratify the heterogeneity of cellular systems based on their electrophysiology. Emerging applications range from fundamental life-science and drug assessment research to point-of-care diagnostics and precision medicine. Recently, novel chip designs and data analytic strategies are laying the foundation for multiparametric cell characterization and subpopulation distinction, which are essential to understand biological function, follow disease progression and monitor cell behaviour in microsystems. In this tutorial review, we present a comparative survey of the approaches to elucidate cellular and subcellular features from impedance cytometry data, covering the related subjects of device design, data analytics (i.e., signal processing, dielectric modelling, population clustering), and phenotyping applications. We give special emphasis to the exciting recent developments of the technique (timeframe 2017-2020) and provide our perspective on future challenges and directions. Its synergistic application with microfluidic separation, sensor science and machine learning can form an essential toolkit for label-free quantification and isolation of subpopulations to stratify heterogeneous biosystems.
Collapse
Affiliation(s)
- Carlos Honrado
- Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA 22904, USA.
| | | | | | | |
Collapse
|
8
|
Younis MS, Abououf EAER, Ali AES, Abd elhady SM, Wassef RM. In vitro Effect of Silver Nanoparticles on Blastocystis hominis. Int J Nanomedicine 2020; 15:8167-8173. [PMID: 33116522 PMCID: PMC7588274 DOI: 10.2147/ijn.s272532] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 09/24/2020] [Indexed: 11/23/2022] Open
Abstract
INTRODUCTION This study aims to assess the efficacy of silver nanoparticles (Ag Nps) alone and combined with metronidazole (Ag Nps + MTZ) as potential alternative therapeutic agents for Blastocystis hominis. METHODS The parasites were challenged with Ag Nps, Ag Nps + MTZ and MTZ. To assess the efficacy of drugs, counting of viable parasites was done after 1, 2, and 3 hours of adding the drugs. RESULTS Blastocystis hominis count was reduced by 20.72%, 28.23%, and 18.92% after one hour of adding Ag Nps, Ag Nps + MTZ, and MTZ, respectively. Cysts count was further reduced by 51.49%, 61.61%, and 40.78% after 2 hours and by 71.69%, 79.67%, and 62.65% after 3 hours of adding the drugs in the same order, respectively. CONCLUSION There was a statistically significant difference (P<0.05) in the in vitro growth inhibition of the parasite over the different time intervals when using the tested drugs against the control drug.
Collapse
Affiliation(s)
- Mohamed Saad Younis
- Medical Parasitology Department, Faculty of Medicine, Benha University, Benha, Egypt
| | | | - Ali El saeed Ali
- Medical Parasitology Department, Faculty of Medicine, Benha University, Benha, Egypt
| | | | - Rita Maher Wassef
- Medical Parasitology Department, Faculty of Medicine, Helwan University, Cairo, Egypt
| |
Collapse
|
9
|
Determination of the Empirical Electrokinetic Equilibrium Condition of Microorganisms in Microfluidic Devices. BIOSENSORS-BASEL 2020; 10:bios10100148. [PMID: 33086549 PMCID: PMC7603120 DOI: 10.3390/bios10100148] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/12/2020] [Accepted: 10/16/2020] [Indexed: 12/16/2022]
Abstract
The increased concern regarding emerging pathogens and antibiotic resistance has drawn interest in the development of rapid and robust microfluidic techniques to analyze microorganisms. The novel parameter known as the electrokinetic equilibrium condition (EEEC) was presented in recent studies, providing an approach to analyze microparticles in microchannels employing unique electrokinetic (EK) signatures. While the EEEC shows great promise, current estimation approaches can be time-consuming or heavily user-dependent for accurate values. The present contribution aims to analyze existing approaches for estimating this parameter and modify the process into an accurate yet simple technique for estimating the EK behavior of microorganisms in insulator-based microfluidic devices. The technique presented here yields the parameter called the empirical electrokinetic equilibrium condition (eEEEC) which works well as a value for initial approximations of trapping conditions in insulator-based EK (iEK) microfluidic systems. A total of six types of microorganisms were analyzed in this study (three bacteria and three bacteriophages). The proposed approach estimated eEEEC values employing images of trapped microorganisms, yielding high reproducibility (SD 5.0–8.8%). Furthermore, stable trapping voltages (sTVs) were estimated from eEEEC values for distinct channel designs to test that this parameter is system-independent and good agreement was obtained when comparing estimated sTVs vs. experimental values (SD 0.3–19.6%). The encouraging results from this work were used to generate an EK library of data, available on our laboratory website. The data in this library can be used to design tailored iEK microfluidic devices for the analysis of microorganisms.
Collapse
|
10
|
Quevedo DF, Lentz CJ, Coll de Peña A, Hernandez Y, Habibi N, Miki R, Lahann J, Lapizco-Encinas BH. Electrokinetic characterization of synthetic protein nanoparticles. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:1556-1567. [PMID: 33134000 PMCID: PMC7590587 DOI: 10.3762/bjnano.11.138] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 09/29/2020] [Indexed: 05/11/2023]
Abstract
The application of nanoparticle in medicine is promising for the treatment of a wide variety of diseases. However, the slow progress in the field has resulted in relatively few therapies being translated into the clinic. Anisotropic synthetic protein nanoparticles (ASPNPs) show potential as a next-generation drug-delivery technology, due to their biocompatibility, biodegradability, and functionality. Even though ASPNPs have the potential to be used in a variety of applications, such as in the treatment of glioblastoma, there is currently no high-throughput technology for the processing of these particles. Insulator-based electrokinetics employ microfluidics devices that rely on electrokinetic principles to manipulate micro- and nanoparticles. These miniaturized devices can selectively trap and enrich nanoparticles based on their material characteristics, and subsequently release them, which allows for particle sorting and processing. In this study, we use insulator-based electrokinetic (EK) microdevices to characterize ASPNPs. We found that anisotropy strongly influences electrokinetic particle behavior by comparing compositionally identical anisotropic and non-anisotropic SPNPs. Additionally, we were able to estimate the empirical electrokinetic equilibrium parameter (eE EEC) for all SPNPs. This particle-dependent parameter can allow for the design of various separation and purification processes. These results show how promising the insulator-based EK microdevices are for the analysis and purification of clinically relevant SPNPs.
Collapse
Affiliation(s)
- Daniel F Quevedo
- Biointerfaces Institute, University of Michigan - Ann Arbor, Ann Arbor MI, USA
- Biomedical Engineering, University of Michigan - Ann Arbor, Ann Arbor MI, USA
| | - Cody J Lentz
- Microscale Bioseparations Laboratory and Biomedical Engineering Department, Rochester Institute of Technology, Rochester NY, USA
| | - Adriana Coll de Peña
- Microscale Bioseparations Laboratory and Biomedical Engineering Department, Rochester Institute of Technology, Rochester NY, USA
| | - Yazmin Hernandez
- Biointerfaces Institute, University of Michigan - Ann Arbor, Ann Arbor MI, USA
- Biomedical Engineering, University of Michigan - Ann Arbor, Ann Arbor MI, USA
| | - Nahal Habibi
- Biointerfaces Institute, University of Michigan - Ann Arbor, Ann Arbor MI, USA
- Chemical Engineering, University of Michigan - Ann Arbor, Ann Arbor MI, USA
| | - Rikako Miki
- Biointerfaces Institute, University of Michigan - Ann Arbor, Ann Arbor MI, USA
- Biomedical Engineering, University of Michigan - Ann Arbor, Ann Arbor MI, USA
| | - Joerg Lahann
- Biointerfaces Institute, University of Michigan - Ann Arbor, Ann Arbor MI, USA
- Biomedical Engineering, University of Michigan - Ann Arbor, Ann Arbor MI, USA
- Chemical Engineering, University of Michigan - Ann Arbor, Ann Arbor MI, USA
| | - Blanca H Lapizco-Encinas
- Microscale Bioseparations Laboratory and Biomedical Engineering Department, Rochester Institute of Technology, Rochester NY, USA
| |
Collapse
|
11
|
Habibi S, Joshi PU, Mi X, Heldt CL, Minerick AR. Changes in Membrane Dielectric Properties of Porcine Kidney Cells Provide Insight into the Antiviral Activity of Glycine. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:8344-8356. [PMID: 32614601 DOI: 10.1021/acs.langmuir.0c00175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The ability to monitor the status and progression of viral infections is important for development and screening of new antiviral drugs. Previous research illustrated that the osmolyte glycine (Gly) reduced porcine parvovirus (PPV) infection in porcine kidney (PK-13) cells by stabilizing the capsid protein and preventing virus capsid assembly into viable virus particles. Dielectrophoresis (DEP) was examined herein as a noninvasive, electric field- and frequency-dependent tool for real-time monitoring of PK-13 cell responses to obtain information about membrane barrier functionality and polarization. DEP responses of PK-13 cells were compared to those of PPV-infected cells in the absence and presence of the osmolyte glycine. With infection progression, PK-13 DEP spectra shifted toward lower frequencies, reducing crossover frequencies (fCO). The spherical single-shell model was used to extract PK-13 cell dielectric properties. Upon PPV infection, specific membrane capacitance increased over the time progression of virus attachment, penetration, and capsid protein production and assembly. Following glycine treatment, the DEP spectra displayed attenuated fCO and specific membrane capacitance values shifted back toward uninfected PK-13 cell values. These results suggest that DEP can be used to noninvasively monitor the viral infection cycle and screen antiviral compounds. DEP can augment traditional tools by elucidating membrane polarization changes related to drug mechanisms that interrupt the virus infection cycle.
Collapse
Affiliation(s)
- Sanaz Habibi
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Pratik U Joshi
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Xue Mi
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Caryn L Heldt
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Adrienne R Minerick
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan 49931, United States
| |
Collapse
|
12
|
Advances and applications of isomotive dielectrophoresis for cell analysis. Anal Bioanal Chem 2020; 412:3813-3833. [DOI: 10.1007/s00216-020-02590-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 03/03/2020] [Accepted: 03/09/2020] [Indexed: 01/31/2023]
|
13
|
Torres-Castro K, Honrado C, Varhue WB, Farmehini V, Swami NS. High-throughput dynamical analysis of dielectrophoretic frequency dispersion of single cells based on deflected flow streamlines. Anal Bioanal Chem 2020; 412:3847-3857. [PMID: 32128645 DOI: 10.1007/s00216-020-02467-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/21/2020] [Accepted: 01/28/2020] [Indexed: 12/14/2022]
Abstract
Phenotypic quantification of cells based on their plasma membrane capacitance and cytoplasmic conductivity, as determined by their dielectrophoretic frequency dispersion, is often used as a marker for their biological function. However, due to the prevalence of phenotypic heterogeneity in many biological systems of interest, there is a need for methods capable of determining the dielectrophoretic dispersion of single cells at high throughput and without the need for sample dilution. We present a microfluidic device methodology wherein localized constrictions in the microchannel are used to enhance the field delivered by adjoining planar electrodes, so that the dielectrophoresis level and direction on flow-focused cells can be determined on each traversing cell in a high-throughput manner based on their deflected flow streamlines. Using a sample of human red blood cells diluted to 2.25 × 108 cells/mL, the dielectrophoretic translation of single cells traversing at a flow rate of 1.68 μL/min is measured at a throughput of 1.1 × 105 cells/min, to distinguish positive versus negative dielectrophoresis and determine their crossover frequency in media of differing conductivity for validation of the computed membrane capacitance to that from prior methods. We envision application of this dynamic dielectrophoresis (Dy-DEP) method towards high-throughput measurement of the dielectric dispersion of single cells to stratify phenotypic heterogeneity of a particular sample based on their DEP crossover frequency, without the need for significant sample dilution. Grapical abstract.
Collapse
Affiliation(s)
- Karina Torres-Castro
- Electrical and Computer Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Carlos Honrado
- Electrical and Computer Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Walter B Varhue
- Electrical and Computer Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Vahid Farmehini
- Electrical and Computer Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Nathan S Swami
- Electrical and Computer Engineering, University of Virginia, Charlottesville, VA, 22904, USA.
- Chemistry, University of Virginia, Charlottesville, VA, 22904, USA.
| |
Collapse
|
14
|
Hill N, Lapizco-Encinas BH. Continuous flow separation of particles with insulator-based dielectrophoresis chromatography. Anal Bioanal Chem 2020; 412:3891-3902. [DOI: 10.1007/s00216-019-02308-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/15/2019] [Accepted: 11/27/2019] [Indexed: 01/10/2023]
|
15
|
Khandelwal AV, Singh A, Pal N, Kumar R, Goel G, Gupta S. AC Conductivity Measurements of Ultradilute Colloidal Suspensions in HEPES Buffer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:14725-14733. [PMID: 31626736 DOI: 10.1021/acs.langmuir.9b01464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Impedance spectroscopy was used to probe the AC conductivity of extremely dilute colloidal suspensions (2.5 × 10-5 ≤ Φw/v ≤ 4.0 × 10-2) comprising of polystyrene microspheres (PS; κa ≫ 1 and ζ = -65 mV), gold nanoparticles (Au NPs; κa > 1 and ζ = -26 mV), and Au-coated PS metallodielectric particles (Au-PS) in HEPES buffer. When AC electric fields of strength 10 mV and 1 MHz were applied via 100 μm gap interdigitated microelectrodes across 10 μL samples, a highly resistive (θcapacitive < 1°) and nonmonotonic response was obtained with particle concentrations at steady state. While the suspensions were less resistive (than the buffer) below a critical concentration, they became more resistive above it. More interestingly, particle-particle interactions took place in suspensions with concentrations as low as 0.005% w/v. We believe this unique behavior is linked to the ion size asymmetry in the HEPES molecule that provides an ideal microenvironment for counterionic polarization around the particles. The exact mechanism of polarization in HEPES, however, still remains elusive as the current theoretical models for simple electrolytes fail to explain our data.
Collapse
Affiliation(s)
- Aditya Vikram Khandelwal
- Department of Chemical Engineering , Indian Institute of Technology Delhi , New Delhi 110016 , India
| | - Akash Singh
- Department of Chemical Engineering , Indian Institute of Technology Delhi , New Delhi 110016 , India
| | - Namrata Pal
- Department of Chemical Engineering , Indian Institute of Technology Delhi , New Delhi 110016 , India
| | - Rajdeep Kumar
- Department of Chemical Engineering , Indian Institute of Technology Delhi , New Delhi 110016 , India
| | - Gaurav Goel
- Department of Chemical Engineering , Indian Institute of Technology Delhi , New Delhi 110016 , India
| | - Shalini Gupta
- Department of Chemical Engineering , Indian Institute of Technology Delhi , New Delhi 110016 , India
| |
Collapse
|
16
|
Habibi S, Lee HY, Moncada-Hernandez H, Gooding J, Minerick AR. Impacts of low concentration surfactant on red blood cell dielectrophoretic responses. BIOMICROFLUIDICS 2019; 13:054101. [PMID: 31531153 PMCID: PMC6746619 DOI: 10.1063/1.5113735] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/02/2019] [Indexed: 06/10/2023]
Abstract
Cell dielectrophoretic responses have been extensively studied for biomarker expression, blood typing, sepsis, circulating tumor cell separations, and others. Surfactants are often added to the analytical buffer in electrokinetic cellular microfluidic systems to lower surface/interfacial tensions. In nonelectrokinetic systems, surfactants influence cell size, shape, and agglomeration; this has not been systematically documented in electrokinetic systems. In the present work, the impacts of the Triton X-100 surfactant on human red blood cells (RBCs) were explored via ultraviolet-visible spectroscopy (UV-Vis) and dielectrophoresis (DEP) to compare nonelectrokinetic and electrokinetic responses, respectively. The UV-Vis spectra of Triton X-100 treated RBCs were dramatically different from that of native RBCs. DEP responses of RBCs were compared to RBCs treated with low concentrations of Triton X-100 (0.07-0.17 mM) to ascertain surfactant effects on dielectric properties. A star-shaped electrode design was used to quantify RBC dielectric properties by fitting a single-shell oblate cell model to experimentally-derived DEP spectra. The presence of 0.07 and 0.11 mM of Triton X-100 shifted the RBC's DEP spectra yielding lower crossover frequencies ( f C O ) . The single-shell oblate model revealed that cell radius and membrane permittivity are the dominant influencers of DEP spectral shifts. The trends observed were similar for 0.11 mM and 0.07 mM Triton X-100 treated cells. However, a further increase of Triton X-100 to 0.17 mM caused cells to only exhibit negative DEP. The magnitude of the DEP force increased with Triton X-100 concentration. This work indicates that dynamic surfactant interactions with cell membranes alter cell dielectric responses and properties.
Collapse
|
17
|
Hassan D, Farghali M, Eldeek H, Gaber M, Elossily N, Ismail T. Antiprotozoal activity of silver nanoparticles against Cryptosporidium parvum oocysts: New insights on their feasibility as a water disinfectant. J Microbiol Methods 2019; 165:105698. [PMID: 31446036 DOI: 10.1016/j.mimet.2019.105698] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 08/19/2019] [Accepted: 08/21/2019] [Indexed: 02/04/2023]
Abstract
Cryptosporidium is a protozoan of extremely medical and veterinary impact; whose oocysts donate a considerable resistant to the water treatment processes. Therefore, this study aimed to explore the impacts of silver nanoparticles (AgNPs) on count and viability of the Cryptosporidium parvum (CP) isolated from different tap water samples. The oocysts were exposed to AgNPs at different dosages of 0.05, 0.1 and 1 ppm for several contact times (30 min to 4 h). The results showed a significant decrease in oocyst count and viability in a dose-dependent manner. Additionally, AgNPs at a conc. of 1 ppm for 30 min and 0.1 ppm for 1 h reduced the oocysts by 97.2 and 94.4%, respectively. Comparatively, there was a noticeable increase in the oocyst's viability at 2 and 4 h, which emphasized that the time of contact between AgNPs and CP was not a major influencing factor for successful application of AgNPs in the nano-water treatment.
Collapse
Affiliation(s)
- Dalia Hassan
- Department of Animal and Poultry Hygiene & Environmental Sanitation, Faculty of Veterinary Medicine, Assiut University, 71526, Egypt
| | - Mohamed Farghali
- Department of Animal and Poultry Hygiene & Environmental Sanitation, Faculty of Veterinary Medicine, Assiut University, 71526, Egypt.
| | - Hanan Eldeek
- Department of Parasitology, Faculty of Medicine, Assiut University, 71526, Egypt
| | - Mona Gaber
- Department of Parasitology, Faculty of Medicine, Assiut University, 71526, Egypt
| | - Nahed Elossily
- Department of Parasitology, Faculty of Medicine, Assiut University, 71526, Egypt
| | - Taghreed Ismail
- Public Health and Community Medicine Department, Assiut University, 71526, Egypt
| |
Collapse
|
18
|
Moore JH, Varhue WB, Su YH, Linton SS, Farmehini V, Fox TE, Matters GL, Kester M, Swami NS. Conductance-Based Biophysical Distinction and Microfluidic Enrichment of Nanovesicles Derived from Pancreatic Tumor Cells of Varying Invasiveness. Anal Chem 2019; 91:10424-10431. [PMID: 31333013 DOI: 10.1021/acs.analchem.8b05745] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Diagnostics based on exosomes and other extracellular vesicles (EVs) are emerging as strategies for informing cancer progression and therapies, since the lipid content and macromolecular cargo of EVs can provide key phenotypic and genotypic information on the parent tumor cell and its microenvironment. We show that EVs derived from more invasive pancreatic tumor cells that express high levels of tumor-specific surface proteins and are composed of highly unsaturated lipids that increase membrane fluidity, exhibit significantly higher conductance versus those derived from less invasive tumor cells, based on dielectrophoresis measurements. Furthermore, through specific binding of the EVs to gold nanoparticle-conjugated antibodies, we show that these conductance differences can be modulated in proportion to the type as well as level of expressed tumor-specific antigens, thereby presenting methods for selective microfluidic enrichment and cytometry-based quantification of EVs based on invasiveness of their parent cell.
Collapse
Affiliation(s)
| | | | | | - Samuel S Linton
- Biochemistry and Molecular Biology , Pennsylvania State University College of Medicine , Hershey , Pennsylvania 17033 , United States
| | | | | | - Gail L Matters
- Biochemistry and Molecular Biology , Pennsylvania State University College of Medicine , Hershey , Pennsylvania 17033 , United States
| | | | | |
Collapse
|
19
|
Analysis of Bacteriophages with Insulator-Based Dielectrophoresis. MICROMACHINES 2019; 10:mi10070450. [PMID: 31277396 PMCID: PMC6680707 DOI: 10.3390/mi10070450] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 06/28/2019] [Accepted: 06/30/2019] [Indexed: 02/07/2023]
Abstract
Bacterial viruses or phages have great potential in the medical and agricultural fields as alternatives to antibiotics to control nuisance populations of pathogenic bacteria. However, current analysis and purification protocols for phages tend to be resource intensive and have numbers of limitations, such as impacting phage viability. The present study explores the potential of employing the electrokinetic technique of insulator-based dielectrophoresis (iDEP) for virus assessment, separation and enrichment. In particular, the application of the parameter "trapping value" (Tv) is explored as a standardized iDEP signature for each phage species. The present study includes mathematical modeling with COMSOL Multiphysics and extensive experimentation. Three related, but genetically and structurally distinct, phages were studied: Salmonella enterica phage SPN3US, Pseudomonas aeruginosa phage ϕKZ and P. chlororaphis phage 201ϕ2-1. This is the first iDEP study on bacteriophages with large and complex virions and the results illustrate their virions can be successfully enriched with iDEP systems and still retain infectivity. In addition, our results indicate that characterization of the negative dielectrophoretic response of a phage in terms of Tv could be used for predicting individual virus behavior in iDEP systems. The findings reported here can contribute to the establishment of protocols to analyze, purify and/or enrich samples of known and unknown phages.
Collapse
|
20
|
Crowther CV, Hilton SH, Kemp L, Hayes MA. Isolation and identification of Listeria monocytogenes utilizing DC insulator-based dielectrophoresis. Anal Chim Acta 2019; 1068:41-51. [PMID: 31072476 DOI: 10.1016/j.aca.2019.03.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 03/04/2019] [Accepted: 03/08/2019] [Indexed: 02/06/2023]
Abstract
Foodborne pathogens pose one of the greatest challenges facing public health in the modern day. One important pathogen, Listeria monocytogenes, is known to be challenging to detect and identify. Three serovars cause most of the Listeria related food-borne illnesses, which the Centers for Disease Control currently utilizes a combination of pulsed-field gel electrophoresis and whole genome sequencing for identification and the determination of clusters and outbreaks. There is a potential method for rapid collection of epidemiological information by exploiting the electrokinetic and dielectrophoretic properties of the L. monocytogenes serovars. Using dielectrophoresis, the three most commonly identified serovars of L. monocytogenes can be distinguished from each other. The electrokinetic and dielectrophoretic mobilities of each serovar was determined through a combination of electrokinetic velocity and dielectrophoretic trapping assessments, in conjunction with finite element multi-physics modeling. A mathematical model of the data, which defines the various factors of dielectrophoretic trapping, is utilized and verified based on the behavior of L. monocytogenes in the microchannel. The trapping condition for the serovars were evaluated as 2.8±0.2×109, 2.2±0.2×109, and 2.2±0.3×109Vm-2 and the electrokinetic mobility was assessed to be 19±0.7, 17±0.7, and for the L. monocytogenes serovars 1/2a, 1/2b, and 4b, respectively.
Collapse
Affiliation(s)
- Claire V Crowther
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
| | | | - LaKeta Kemp
- Phoenix Research Institute, Phoenix, AZ, USA
| | - Mark A Hayes
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA.
| |
Collapse
|
21
|
Reale R, De Ninno A, Businaro L, Bisegna P, Caselli F. A simple electrical approach to monitor dielectrophoretic focusing of particles flowing in a microchannel. Electrophoresis 2019; 40:1400-1407. [PMID: 30661234 DOI: 10.1002/elps.201800423] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 12/20/2018] [Accepted: 01/02/2019] [Indexed: 02/01/2023]
Abstract
This paper reports an impedance-based system for the quantitative assessment of dielectrophoretic (DEP) focusing of single particles flowing in a microchannel. Particle lateral positions are detected in two electrical sensing zones placed before and after a DEP-focusing region, respectively. In each sensing zone, particle lateral positions are estimated using the unbalance between the opposite pulses of a differential current signal obtained with a straightforward coplanar electrode configuration. The system is used to monitor the focusing of polystyrene beads of 7 or 10 μm diameter, under various conditions of DEP field intensities and flow rates that produce different degrees of focusing. This electrical approach represents a simple and valuable alternative to optical methods for monitoring of particle focusing systems.
Collapse
Affiliation(s)
- Riccardo Reale
- Department of Civil Engineering and Computer Science, University of Rome Tor Vergata, Rome, Italy
| | - Adele De Ninno
- Department of Civil Engineering and Computer Science, University of Rome Tor Vergata, Rome, Italy
| | - Luca Businaro
- Institute for Photonics and Nanotechnologies, Italian National Research Council, Rome, Italy
| | - Paolo Bisegna
- Department of Civil Engineering and Computer Science, University of Rome Tor Vergata, Rome, Italy
| | - Federica Caselli
- Department of Civil Engineering and Computer Science, University of Rome Tor Vergata, Rome, Italy
| |
Collapse
|
22
|
Rohani A, Moore JH, Su YH, Stagnaro V, Warren C, Swami NS. Single-cell electro-phenotyping for rapid assessment of Clostridium difficile heterogeneity under vancomycin treatment at sub-MIC (minimum inhibitory concentration) levels. SENSORS AND ACTUATORS. B, CHEMICAL 2018; 276:472-480. [PMID: 30369719 PMCID: PMC6201234 DOI: 10.1016/j.snb.2018.08.137] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Current methods for measurement of antibiotic susceptibility of pathogenic bacteria are highly reliant on microbial culture, which is time consuming (requires > 16 hours), especially at near minimum inhibitory concentration (MIC) levels of the antibiotic. We present the use of single-cell electrophysiology-based microbiological analysis for rapid phenotypic identification of antibiotic susceptibility at near-MIC levels, without the need for microbial culture. Clostridium difficile (C. difficile) is the single most common cause of antibiotic-induced enteric infection and disease recurrence is common after antibiotic treatments to suppress the pathogen. Herein, we show that de-activation of C. difficile after MIC-level vancomycin treatment, as validated by microbiological growth assays, can be ascertained rapidly by measuring alterations to the microbial cytoplasmic conductivity that is gauged by the level of positive dielectrophoresis (pDEP) and the frequency spectra for co-field electro-rotation (ROT). Furthermore, this single-cell electrophysiology technique can rapidly identify and quantify the live C. difficile subpopulation after vancomycin treatment at sub-MIC levels, whereas methods based on measurement of the secreted metabolite toxin or the microbiological growth rate can identify this persistent C. difficile subpopulation only after 24 hours of microbial culture, without any ability to quantify the subpopulation. The application of multiplexed versions of this technique is envisioned for antibiotic susceptibility screening.
Collapse
Affiliation(s)
- Ali Rohani
- Electrical & Computer Engineering, University of Virginia
| | - John H. Moore
- Electrical & Computer Engineering, University of Virginia
| | - Yi-Hsuan Su
- Electrical & Computer Engineering, University of Virginia
| | | | - Cirle Warren
- Infectious Diseases, School of Medicine, University of Virginia
| | - Nathan S. Swami
- Electrical & Computer Engineering, University of Virginia
- Corresponding author: 351 McCormick Road, Charlottesville, VA 22904-1000;
| |
Collapse
|
23
|
Huo ZY, Li GQ, Yu T, Feng C, Lu Y, Wu YH, Yu C, Xie X, Hu HY. Cell Transport Prompts the Performance of Low-Voltage Electroporation for Cell Inactivation. Sci Rep 2018; 8:15832. [PMID: 30361540 PMCID: PMC6202345 DOI: 10.1038/s41598-018-34027-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 10/05/2018] [Indexed: 11/09/2022] Open
Abstract
The inactivation of pathogens in liquids has broad applications, ranging from water disinfection to food pasteurization. However, common cell inactivation methods (e.g., chlorination, ultraviolet radiation and thermal treatment) have significant drawbacks such as carcinogenic byproduct formation, energy intensiveness and/or nutrient structure destruction. Here, we fabricated a new approach to address these challenges by applying a low-voltage electroporation disinfection cell (EDC) and investigate the critical mechanisms of cell transport to allow high inactivation performance. The EDC prototypes were equipped with two one-dimensional (1D) nanostructure-assisted electrodes that enabled high electric field strength (>107 V m−1) near the electrode surface with a low applied voltage (1 V). We have identified that during electroporation disinfection, electrophoresis, dielectrophoresis and hydraulic flow are the three major mechanisms which transport cells into the vicinity of the electrode surface to achieve superior disinfection performance. The EDC treated 70 ml of bacteria sample with an initial cell concentration of 107 CFU ml−1 and achieved complete bacteria inactivation (survival rate <0.00001%; no live bacteria detected). Our findings will help to establish a foundation for the future development and implementation of low-voltage electroporation for cell inactivation.
Collapse
Affiliation(s)
- Zheng-Yang Huo
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, PR China.,School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, United States
| | - Guo-Qiang Li
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, PR China
| | - Tong Yu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, PR China
| | - Chao Feng
- Institute for Advanced Study, Tsinghua University, Beijing, 100084, PR China
| | - Yun Lu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, PR China
| | - Yin-Hu Wu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, PR China
| | - Cecilia Yu
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, United States
| | - Xing Xie
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, United States.
| | - Hong-Ying Hu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, PR China. .,Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen, 518055, PR, China.
| |
Collapse
|
24
|
Lejard-Malki R, Follet J, Vlandas A, Senez V. Selective electrohydrodynamic concentration of waterborne parasites on a chip. LAB ON A CHIP 2018; 18:3310-3322. [PMID: 30283951 DOI: 10.1039/c8lc00840j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Concentrating diluted samples is a key step to improve detection capabilities. The wise use of scaling laws shows the advantages of working with sub-microliter-sized samples. Rapid progress in MEMS technologies has driven the design of integrated platforms performing many biochemical operations. Here we report a new concentrator device based on electro-hydrodynamic forces which can be easily integrated into electrowetting-on-dielectric (EWOD) platforms. This approach is label-free and applicable to a wide range of micro-objects. The detection and analysis of two common waterborne parasites, Cryptosporidium and Giardia, is a perfect test case due to their global health relevance. By fully controlling the interplay of the various forces acting on the micron-sized Cryptosporidium parvum and Cryptosporidium muris oocysts, we show that it is possible to concentrate them on the side of a 10 μL initial drop and then extract them efficiently from a droplet of a few hundred nanoliters. We performed a finite element modeling of the forces acting on the parasites' oocysts to optimize the electrodes' shapes. We obtained state-of-the-art concentration factors of 12 ± 0.4 times and 2 to 4 times in the sub-region of the drop and the extracted droplet, respectively, with an efficiency of 70 ± 6%. Furthermore, this device had the ability to selectively concentrate parasites of different species out of a mix. We demonstrated this by segregating C. parvum oocysts from either Giardia lamblia cysts or its related species, C. muris oocysts.
Collapse
Affiliation(s)
- Romuald Lejard-Malki
- CNRS, ISEN, UMR 8520 - IEMN, Univ. Lille, Avenue Poincaré, C.S. 60069, 59652 Villeneuve d'Ascq cedex, Lille F-59000, France.
| | | | | | | |
Collapse
|
25
|
Abstract
The ability to separate analytes with increasingly similar properties drives the field of separation science. One way to achieve such separations is using trapping and streaming dielectrophoresis (DEP), which directly exploits the subtle differences in the electrophysical properties of analytes. The non-uniform fields necessary for DEP can be formed using various insulator shapes in microchannels. Current insulator shapes include triangles, diamonds, circles, and rectangles. However, all of these insulators pose problems for trapping, streaming, and sorting (deflection) as the induced fields/gradients are not behaviorally consistent across the lateral dimension. This leads to analytes experiencing different forces depending on their pathline in the microchannel and result in low resolution separations. Based on an iterative process that explored approximately 40 different insulator shapes, a design was chosen that indicated improved particle streamlines, better trapping efficiency, and consistent electrical environments across the lateral dimension. The design was assessed by simulations where the electric field, gradient of the electric field squared, and the ratio of the two were plotted. The improved design includes a unique new multi-length scale element. The multi-length scale structure streamlines the analyte(s) and improves homogeneity in the lateral dimension, while still achieving high gradients necessary for analyte separation using DEP. The design is calculated to keep analytes on the centerline which should improve resolution, and eliminate extraneous trapping zones. Behaviors consistent with the features of the simulations were observed in proof of principle experiments using representative test probes.
Collapse
Affiliation(s)
- Claire V Crowther
- Arizona State University, School of Molecular Sciences, Mail Stop 1604, Tempe, AZ 85287, USA.
| | | |
Collapse
|
26
|
Tada S, Omi Y, Eguchi M. Analysis of the dielectrophoretic properties of cells using the isomotive AC electric field. BIOMICROFLUIDICS 2018; 12:044103. [PMID: 30034566 PMCID: PMC6035052 DOI: 10.1063/1.5031054] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 06/06/2018] [Indexed: 06/08/2023]
Abstract
Various microfluidic devices utilizing the principle of dielectrophoresis (DEP) have been developed to separate, concentrate, and characterize biological cells; however, their performance is still limited by a lack of quantitative characterization. We addressed this limitation by employing a method capable of accurately quantifying a cell's response to an imposed field gradient. In this study, a simple method using a newly designed Creek-gap electrode was proposed, and the electrokinetic behavior of cells was characterized by DEP velocimetry under the exposure of an approximately constant gradient of electric field square established along the gap of the electrodes. Together with the numerical prediction of the electric field based on three-dimensional electric field analysis, the magnitude of DEP forces and the real part of the Clausius-Mossotti factor of cells were deduced from their movement. Results demonstrated that the proposed method was applicable to the determination of the dielectrophoretic properties of cells.
Collapse
Affiliation(s)
- Shigeru Tada
- Department of Applied Physics, National Defense Academy, Yokosuka, Kanagawa 239-8686, Japan
| | - Yui Omi
- Department of Applied Physics, National Defense Academy, Yokosuka, Kanagawa 239-8686, Japan
| | - Masanori Eguchi
- Fuzzy Logic Systems Institute, Iizuka, Fukuoka 820-0067, Japan
| |
Collapse
|
27
|
Vande Burgt NH, Auer A, Zintl A. Comparison of in vitro viability methods for Cryptosporidium oocysts. Exp Parasitol 2018. [DOI: 10.1016/j.exppara.2018.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
28
|
Rohani A, Moore JH, Kashatus JA, Sesaki H, Kashatus DF, Swami NS. Label-Free Quantification of Intracellular Mitochondrial Dynamics Using Dielectrophoresis. Anal Chem 2017; 89:5757-5764. [PMID: 28475301 PMCID: PMC5463269 DOI: 10.1021/acs.analchem.6b04666] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 05/05/2017] [Indexed: 01/24/2023]
Abstract
Mitochondrial dynamics play an important role within several pathological conditions, including cancer and neurological diseases. For the purpose of identifying therapies that target aberrant regulation of the mitochondrial dynamics machinery and characterizing the regulating signaling pathways, there is a need for label-free means to detect the dynamic alterations in mitochondrial morphology. We present the use of dielectrophoresis for label-free quantification of intracellular mitochondrial modifications that alter cytoplasmic conductivity, and these changes are benchmarked against label-based image analysis of the mitochondrial network. This is validated by quantifying the mitochondrial alterations that are carried out by entirely independent means on two different cell lines: human embryonic kidney cells and mouse embryonic fibroblasts. In both cell lines, the inhibition of mitochondrial fission that leads to a mitochondrial structure of higher connectivity is shown to substantially enhance conductivity of the cell interior, as apparent from the significantly higher positive dielectrophoresis levels in the 0.5-15 MHz range. Using single-cell velocity tracking, we show ∼10-fold higher positive dielectrophoresis levels at 0.5 MHz for cells with a highly connected versus those with a highly fragmented mitochondrial structure, suggesting the feasibility for frequency-selective dielectrophoretic isolation of cells to aid the discovery process for development of therapeutics targeting the mitochondrial machinery.
Collapse
Affiliation(s)
- Ali Rohani
- Department
of Electrical and Computer Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
| | - John H. Moore
- Department
of Electrical and Computer Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Jennifer A. Kashatus
- Department
of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, United States
| | - Hiromi Sesaki
- Department
of Cell Biology, Johns Hopkins University
School of Medicine, Baltimore, Maryland 21205, United States
| | - David F. Kashatus
- Department
of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, United States
| | - Nathan S. Swami
- Department
of Electrical and Computer Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
| |
Collapse
|
29
|
McGrath JS, Honrado C, Spencer D, Horton B, Bridle HL, Morgan H. Analysis of Parasitic Protozoa at the Single-cell Level using Microfluidic Impedance Cytometry. Sci Rep 2017; 7:2601. [PMID: 28572634 PMCID: PMC5454013 DOI: 10.1038/s41598-017-02715-y] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 04/18/2017] [Indexed: 11/24/2022] Open
Abstract
At present, there are few technologies which enable the detection, identification and viability analysis of protozoan pathogens including Cryptosporidium and/or Giardia at the single (oo)cyst level. We report the use of Microfluidic Impedance Cytometry (MIC) to characterise the AC electrical (impedance) properties of single parasites and demonstrate rapid discrimination based on viability and species. Specifically, MIC was used to identify live and inactive C. parvum oocysts with over 90% certainty, whilst also detecting damaged and/or excysted oocysts. Furthermore, discrimination of Cryptosporidium parvum, Cryptosporidium muris and Giardia lamblia, with over 92% certainty was achieved. Enumeration and identification of (oo)cysts can be achieved in a few minutes, which offers a reduction in identification time and labour demands when compared to existing detection methods.
Collapse
Affiliation(s)
- J S McGrath
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom
| | - C Honrado
- Faculty of Physical Sciences and Engineering and Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - D Spencer
- Faculty of Physical Sciences and Engineering and Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - B Horton
- Moredun Scientific, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ, United Kingdom
| | - H L Bridle
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom
| | - H Morgan
- Faculty of Physical Sciences and Engineering and Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom.
| |
Collapse
|
30
|
Fernandez RE, Rohani A, Farmehini V, Swami NS. Review: Microbial analysis in dielectrophoretic microfluidic systems. Anal Chim Acta 2017; 966:11-33. [PMID: 28372723 PMCID: PMC5424535 DOI: 10.1016/j.aca.2017.02.024] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 02/03/2017] [Accepted: 02/20/2017] [Indexed: 12/13/2022]
Abstract
Infections caused by various known and emerging pathogenic microorganisms, including antibiotic-resistant strains, are a major threat to global health and well-being. This highlights the urgent need for detection systems for microbial identification, quantification and characterization towards assessing infections, prescribing therapies and understanding the dynamic cellular modifications. Current state-of-the-art microbial detection systems exhibit a trade-off between sensitivity and assay time, which could be alleviated by selective and label-free microbial capture onto the sensor surface from dilute samples. AC electrokinetic methods, such as dielectrophoresis, enable frequency-selective capture of viable microbial cells and spores due to polarization based on their distinguishing size, shape and sub-cellular compositional characteristics, for downstream coupling to various detection modalities. Following elucidation of the polarization mechanisms that distinguish bacterial cells from each other, as well as from mammalian cells, this review compares the microfluidic platforms for dielectrophoretic manipulation of microbials and their coupling to various detection modalities, including immuno-capture, impedance measurement, Raman spectroscopy and nucleic acid amplification methods, as well as for phenotypic assessment of microbial viability and antibiotic susceptibility. Based on the urgent need within point-of-care diagnostics towards reducing assay times and enhancing capture of the target organism, as well as the emerging interest in isolating intact microbials based on their phenotype and subcellular features, we envision widespread adoption of these label-free and selective electrokinetic techniques.
Collapse
Affiliation(s)
- Renny E Fernandez
- Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA 22904, USA
| | - Ali Rohani
- Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA 22904, USA
| | - Vahid Farmehini
- Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA 22904, USA
| | - Nathan S Swami
- Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA 22904, USA.
| |
Collapse
|
31
|
Singh M. Elucidation of biogenic silver nanoparticles susceptibility towards Escherichia coli: an investigation on the antimicrobial mechanism. IET Nanobiotechnol 2016; 10:276-280. [PMID: 27676374 PMCID: PMC8676372 DOI: 10.1049/iet-nbt.2015.0063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 11/30/2015] [Accepted: 12/08/2015] [Indexed: 01/06/2023] Open
Abstract
Elucidation of the role of silver nanoparticles (AgNPs) in combating bacterial infection is important for the development of new antimicrobial compounds. In this study, several key factors underlying biological effects of biogenic AgNPs were investigated on recombinant Escherichia coli (XL1-Blue) which contains a reporter gene encoding β-galactosidase enzyme. Biogenic AgNPs were prepared from the tea decoction. Cytotoxicity effects were profound on the bacteria tested by the synthesised NPs. The β-galactosidase activity of the released intracellular proteins in the supernatant of E. coli was used as a measure of membrane damage and cellular leakage. Occurrence of a significant amount of β-galactosiadase activity in the supernatant of treated cells clearly demonstrated the formation of holes in the bacterial membrane. Scanning electron microscope pictures visibly indicated destruction of the membrane of the bacteria, which further confirmed membrane damage. The synthesised NPs caused damage of E. coli genomic DNA in a dose dependent manner.
Collapse
Affiliation(s)
- Mukesh Singh
- Department of Biotechnology, Haldia Institute of Technology, HIT campus, Hatiberia, Purba Medinipur, Haldia 721 657, India.
| |
Collapse
|
32
|
Su YH, Rohani A, Warren CA, Swami NS. Tracking Inhibitory Alterations during Interstrain Clostridium difficile Interactions by Monitoring Cell Envelope Capacitance. ACS Infect Dis 2016; 2:544-551. [PMID: 27547818 PMCID: PMC4985749 DOI: 10.1021/acsinfecdis.6b00050] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Indexed: 01/05/2023]
Abstract
![]()
Global threats arising
from the increasing use of antibiotics coupled
with the high recurrence rates of Clostridium difficile (C. difficile) infections (CDI) after standard
antibiotic treatments highlight the role of commensal probiotic microorganisms,
including nontoxigenic C. difficile (NTCD) strains
in preventing CDI due to highly toxigenic C. difficile (HTCD) strains. However, optimization of the inhibitory permutations
due to commensal interactions in the microbiota requires probes capable
of monitoring phenotypic alterations to C. difficile cells. Herein, by monitoring the field screening behavior of the C. difficile cell envelope with respect to cytoplasmic polarization,
we demonstrate that inhibition of the host-cell colonization ability
of HTCD due to the S-layer alterations occurring after its co-culture
with NTCD can be quantitatively tracked on the basis of the capacitance
of the cell envelope of co-cultured HTCD. Furthermore, it is shown
that effective inhibition requires the dynamic contact of HTCD cells
with freshly secreted extracellular factors from NTCD because contact
with the cell-free supernatant causes only mild inhibition. We envision
a rapid method for screening the inhibitory permutations to arrest C. difficile colonization by routinely probing alterations
in the HTCD dielectrophoretic frequency response due to variations
in the capacitance of its cell envelope.
Collapse
Affiliation(s)
- Yi-Hsuan Su
- Department of Electrical & Computer Engineering and ‡Infectious Diseases, School of Medicine, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Ali Rohani
- Department of Electrical & Computer Engineering and ‡Infectious Diseases, School of Medicine, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Cirle A. Warren
- Department of Electrical & Computer Engineering and ‡Infectious Diseases, School of Medicine, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Nathan S. Swami
- Department of Electrical & Computer Engineering and ‡Infectious Diseases, School of Medicine, University of Virginia, Charlottesville, Virginia 22904, United States
| |
Collapse
|
33
|
Bartelt LA, Bolick DT, Kolling GL, Roche JK, Zaenker EI, Lara AM, Noronha FJ, Cowardin CA, Moore JH, Turner JR, Warren CA, Buck GA, Guerrant RL. Cryptosporidium Priming Is More Effective than Vaccine for Protection against Cryptosporidiosis in a Murine Protein Malnutrition Model. PLoS Negl Trop Dis 2016; 10:e0004820. [PMID: 27467505 PMCID: PMC4965189 DOI: 10.1371/journal.pntd.0004820] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 06/11/2016] [Indexed: 01/21/2023] Open
Abstract
Cryptosporidium is a major cause of severe diarrhea, especially in malnourished children. Using a murine model of C. parvum oocyst challenge that recapitulates clinical features of severe cryptosporidiosis during malnutrition, we interrogated the effect of protein malnutrition (PM) on primary and secondary responses to C. parvum challenge, and tested the differential ability of mucosal priming strategies to overcome the PM-induced susceptibility. We determined that while PM fundamentally alters systemic and mucosal primary immune responses to Cryptosporidium, priming with C. parvum (106 oocysts) provides robust protective immunity against re-challenge despite ongoing PM. C. parvum priming restores mucosal Th1-type effectors (CD3+CD8+CD103+ T-cells) and cytokines (IFNγ, and IL12p40) that otherwise decrease with ongoing PM. Vaccination strategies with Cryptosporidium antigens expressed in the S. Typhi vector 908htr, however, do not enhance Th1-type responses to C. parvum challenge during PM, even though vaccination strongly boosts immunity in challenged fully nourished hosts. Remote non-specific exposures to the attenuated S. Typhi vector alone or the TLR9 agonist CpG ODN-1668 can partially attenuate C. parvum severity during PM, but neither as effectively as viable C. parvum priming. We conclude that although PM interferes with basal and vaccine-boosted immune responses to C. parvum, sustained reductions in disease severity are possible through mucosal activators of host defenses, and specifically C. parvum priming can elicit impressively robust Th1-type protective immunity despite ongoing protein malnutrition. These findings add insight into potential correlates of Cryptosporidium immunity and future vaccine strategies in malnourished children. Cryptosporidium attributable morbidities in malnourished children are increasingly recognized. Exactly how malnutrition interferes with host mucosal immunity to diarrheal pathogens and mucosal vaccine responses remains unclear. Dissecting these interactions in an experimental model of cryptosporidiosis can uncover new insights into novel therapeutic approaches against a pathogen for which effective therapies and vaccines are currently unavailable. We demonstrate that although malnutrition diminishes baseline (primary) Th1-type mucosal immunity these deficits can be partially overcome via non-specific mucosal strategies (S. Typhi and CpG) and completely restored after a sub-clinical (low-dose) exposure to viable C. parvum. These results add insight into preventive strategies to help alleviate Cryptosporidium-specific diarrhea in children in low-resource settings and abrogate prolonged post-infection sequelae.
Collapse
Affiliation(s)
- Luther A. Bartelt
- Division of Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
| | - David T. Bolick
- Division of Infectious Diseases and Center for Global Health, University of Virginia, Charlottesville, Virginia, United States of America
| | - Glynis L. Kolling
- Division of Infectious Diseases and Center for Global Health, University of Virginia, Charlottesville, Virginia, United States of America
| | - James K. Roche
- Division of Infectious Diseases and Center for Global Health, University of Virginia, Charlottesville, Virginia, United States of America
| | - Edna I. Zaenker
- Division of Infectious Diseases and Center for Global Health, University of Virginia, Charlottesville, Virginia, United States of America
| | - Ana M. Lara
- Molecular Biology and Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Francisco Jose Noronha
- Division of Infectious Diseases and Center for Global Health, University of Virginia, Charlottesville, Virginia, United States of America
| | - Carrie A. Cowardin
- Division of Infectious Diseases and Center for Global Health, University of Virginia, Charlottesville, Virginia, United States of America
| | - John H. Moore
- Division of Infectious Diseases and Center for Global Health, University of Virginia, Charlottesville, Virginia, United States of America
| | - Jerrold R. Turner
- Department of Pathology, The University of Chicago, Chicago, Illinois, United States of America
- Departments of Pathology and Medicine—Gastroenterology, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
| | - Cirle A. Warren
- Division of Infectious Diseases and Center for Global Health, University of Virginia, Charlottesville, Virginia, United States of America
| | - Gregory A. Buck
- Molecular Biology and Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Richard L. Guerrant
- Division of Infectious Diseases and Center for Global Health, University of Virginia, Charlottesville, Virginia, United States of America
| |
Collapse
|
34
|
Fernandez RE, Koklu A, Mansoorifar A, Beskok A. Platinum black electrodeposited thread based electrodes for dielectrophoretic assembly of microparticles. BIOMICROFLUIDICS 2016; 10:033101. [PMID: 27158295 PMCID: PMC4833733 DOI: 10.1063/1.4946015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 03/13/2016] [Indexed: 05/12/2023]
Abstract
We report dielectrophoretic (DEP) assembly of biological cells and microparticles using platinum-black electrodeposited conductive textile fiber. The three-dimensional conductive structures with high aspect ratios were found to facilitate high electric field regions, as revealed by scanning electron microscope characterization. The effective conducting area (Aeff) and its stability of thread electrodes were estimated using electrochemical methods. Potential of platinum black electrodeposited thread as 3-D electrodes for creating high gradient electrical field for dielectrophoretic assembly of microspheres and Saccharomyces cerevisiae (yeast cells) into 1D and two-dimensional structures over long ranges under the application of low voltages (4-10 Vpp) has been demonstrated. The formation of highly ordered pearl chains of microparticles using thread electrodes when subjected to dielectrophoresis (DEP) has been discussed in detail.
Collapse
Affiliation(s)
- Renny Edwin Fernandez
- Department of Mechanical Engineering, Southern Methodist University , Dallas, Texas 75205, USA
| | - Anil Koklu
- Department of Mechanical Engineering, Southern Methodist University , Dallas, Texas 75205, USA
| | - Amin Mansoorifar
- Department of Mechanical Engineering, Southern Methodist University , Dallas, Texas 75205, USA
| | - Ali Beskok
- Department of Mechanical Engineering, Southern Methodist University , Dallas, Texas 75205, USA
| |
Collapse
|
35
|
Adekanmbi EO, Ueti MW, Rinaldi B, Suarez CE, Srivastava SK. Insulator-based dielectrophoretic diagnostic tool for babesiosis. BIOMICROFLUIDICS 2016; 10:033108. [PMID: 27375817 PMCID: PMC4912563 DOI: 10.1063/1.4954196] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/06/2016] [Indexed: 05/12/2023]
Abstract
Babesia species are obligate intraerythrocytic tick-borne protozoan parasites that are the etiologic agents of babesiosis, a potentially life-threatening, malaria-like illness in humans and animals. Babesia-infected people have been known to suffer from complications including liver problems, severe hemolytic anemia, and kidney failure. As reported by the Food and Drug Administration, 38% of mortality cases observed in transfusion recipients were associated with transfusion transmitted diseases of which babesiosis is the chief culprit. As of now, no tests have been licensed yet for screening blood donors for babesiosis. Current diagnostic tools for babesiosis including enzyme-linked immunosorbent assay, fluorescence in situ hybridization, and polymerase chain reaction are expensive and burdened with multifarious shortcomings. In this research, a low-cost, high-specificity, quick, and easy-to-use insulator-based dielectrophoretic diagnostic tool is developed for characterizing and concentrating Babesia-infected cells in their homogenous mixture with healthy cell population. In this work, a mixture of Babesia-infected (varying parasitemia) and healthy red blood cells (RBCs or erythrocytes) was exposed to non-uniform electric fields in a fabricated microfluidic platform to manipulate and sort the Babesia-infected cells within a minute. At DC voltage configurations of 10 V and 0/6 V in the inlet and the two outlet channels, respectively, the diseased cells were seen to flow in a direction different from the healthy RBCs. Bright field and fluorescence microscopy were utilized to present qualitative differentiation of the healthy erythrocytes from the infected cells. The proposed micro device platform was able to enrich RBCs from 0.1% to ∼70% parasitemia. This device, when finally developed into a point-of-care diagnostic chip, would enhance the detection of Babesia-infected erythrocytes and as well serve as a precursor to babesiosis vaccine development.
Collapse
Affiliation(s)
- Ezekiel O Adekanmbi
- Department of Chemical and Materials Engineering, University of Idaho , Moscow, Idaho 83844-1021, USA
| | - Massaro W Ueti
- Animal Disease Research Unit, Agricultural Research Service, U.S. Department of Agriculture , Pullman, Washington 99164-7030, USA
| | - Brady Rinaldi
- Department of Chemical and Materials Engineering, University of Idaho , Moscow, Idaho 83844-1021, USA
| | - Carlos E Suarez
- Animal Disease Research Unit, Agricultural Research Service, U.S. Department of Agriculture , Pullman, Washington 99164-7030, USA
| | - Soumya K Srivastava
- Department of Chemical and Materials Engineering, University of Idaho , Moscow, Idaho 83844-1021, USA
| |
Collapse
|
36
|
Cheng IF, Chen TY, Chao WC. Increasing local density and purity of molecules/bacteria on a sensing surface from diluted blood using 3D hybrid electrokinetics. BIOMICROFLUIDICS 2016; 10:034116. [PMID: 27375821 PMCID: PMC4902813 DOI: 10.1063/1.4953447] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 05/25/2016] [Indexed: 05/08/2023]
Abstract
We present a long-range and selective nanocolloid/molecular/bacteria concentrator based on 3D hybrid AC electrokinetics (ACEK) that includes AC dielectrophoresis (DEP) and biased AC electroosmosis (ACEO). Through a convergency comb-shaped electrode design, this long-range ACEO allows the effective transport of a high number of targets into the centre of the detection zone. In the proposed 3D hybrid electrokinetics model, 3D ACEO provides long-range transportation, and the 3D DEP provides an effective separation mechanism. Thus, detection targets ranging from nanoscale to micrometers could be selectively concentrated long-range from diluted blood. The proposed design was used for selectively concentrating nanocolloids and bacteria in the diluted blood sample, respectively. Compared to a 3D short-range dipolar electrode configuration, the detection limit of long-range 3D convergency tripolar electrode configuration is one order of magnitude higher. The result also shows that the 3D hybrid ACEK demonstrated a higher purity of any plane above the electrode, which compared positively to the same design of a 2D hybrid ACEK. The concentration factor of the proposed 3D hybrid electrokinetics device increased by several orders of local density and raised the local purity at least 6 orders (from 0.05% to greater than 99.9%). The chip is capable of making a DNA/protein/bacterial aggregate characterized by high local density and purity for further molecular and bacteria detection/analysis.
Collapse
Affiliation(s)
- I-Fang Cheng
- National Nano Device Laboratories, National Applied Research Laboratories , Tainan, Taiwan
| | - Tzu-Ying Chen
- National Nano Device Laboratories, National Applied Research Laboratories , Tainan, Taiwan
| | | |
Collapse
|
37
|
Rohani A, Varhue W, Liao KT, Chou CF, Swami NS. Nanoslit design for ion conductivity gradient enhanced dielectrophoresis for ultrafast biomarker enrichment in physiological media. BIOMICROFLUIDICS 2016; 10:033109. [PMID: 27462378 PMCID: PMC4930445 DOI: 10.1063/1.4954933] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 06/15/2016] [Indexed: 05/12/2023]
Abstract
Selective and rapid enrichment of biomolecules is of great interest for biomarker discovery, protein crystallization, and in biosensing for speeding assay kinetics and reducing signal interferences. The current state of the art is based on DC electrokinetics, wherein localized ion depletion at the microchannel to nanochannel interface is used to enhance electric fields, and the resulting biomarker electromigration is balanced against electro-osmosis in the microchannel to cause high degrees of biomarker enrichment. However, biomarker enrichment is not selective, and the levels fall off within physiological media of high conductivity, due to a reduction in ion concentration polarization and electro-osmosis effects. Herein, we present a methodology for coupling AC electrokinetics with ion concentration polarization effects in nanoslits under DC fields, for enabling ultrafast biomarker enrichment in physiological media. Using AC fields at the critical frequency necessary for negative dielectrophoresis of the biomarker of interest, along with a critical offset DC field to create proximal ion accumulation and depletion regions along the perm-selective region inside a nanoslit, we enhance the localized field and field gradient to enable biomarker enrichment over a wide spatial extent along the nanoslit length. While enrichment under DC electrokinetics relies solely on ion depletion to enhance fields, this AC electrokinetic mechanism utilizes ion depletion as well as ion accumulation regions to enhance the field and its gradient. Hence, biomarker enrichment continues to be substantial in spite of the steady drop in nanostructure perm-selectivity within physiological media.
Collapse
Affiliation(s)
- Ali Rohani
- Department of Electrical and Computer Engineering, University of Virginia , Charlottesville, Virginia 22904, USA
| | - Walter Varhue
- Department of Electrical and Computer Engineering, University of Virginia , Charlottesville, Virginia 22904, USA
| | - Kuo-Tang Liao
- Institute of Physics , Academia Sinica , Taipei 11529, Taiwan
| | - Chia-Fu Chou
- Institute of Physics , Academia Sinica , Taipei 11529, Taiwan
| | - Nathan S Swami
- Department of Electrical and Computer Engineering, University of Virginia , Charlottesville, Virginia 22904, USA
| |
Collapse
|
38
|
Performance and Acceptance of Novel Silver-Impregnated Ceramic Cubes for Drinking Water Treatment in Two Field Sites: Limpopo Province, South Africa and Dodoma Region, Tanzania. WATER 2016. [DOI: 10.3390/w8030095] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
39
|
Silver Nanoparticles Decrease the Viability of Cryptosporidium parvum Oocysts. Appl Environ Microbiol 2016. [PMID: 26497464 DOI: 10.1128/aem.02806‐15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Oocysts of the waterborne protozoan parasite Cryptosporidium parvum are highly resistant to chlorine disinfection. We show here that both silver nanoparticles (AgNPs) and silver ions significantly decrease oocyst viability, in a dose-dependent manner, between concentrations of 0.005 and 500 μg/ml, as assessed by an excystation assay and the shell/sporozoite ratio. For percent excystation, the results are statistically significant for 500 μg/ml of AgNPs, with reductions from 83% for the control to 33% with AgNPs. For Ag ions, the results were statistically significant at 500 and 5,000 μg/ml, but the percent excystation values were reduced only to 66 and 62%, respectively, from 86% for the control. The sporozoite/shell ratio was affected to a greater extent following AgNP exposure, presumably because sporozoites are destroyed by interaction with NPs. We also demonstrated via hyperspectral imaging that there is a dual mode of interaction, with Ag ions entering the oocyst and destroying the sporozoites while AgNPs interact with the cell wall and, at high concentrations, are able to fully break the oocyst wall.
Collapse
|
40
|
Saucedo-Espinosa MA, Rauch MM, LaLonde A, Lapizco-Encinas BH. Polarization behavior of polystyrene particles under direct current and low-frequency (<1 kHz) electric fields in dielectrophoretic systems. Electrophoresis 2015; 37:635-44. [PMID: 26531799 DOI: 10.1002/elps.201500338] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 09/26/2015] [Accepted: 10/22/2015] [Indexed: 11/11/2022]
Abstract
The relative polarization behavior of micron and submicron polystyrene particles was investigated under direct current and very low frequency (<1 kHz) alternating current electric fields. Relative polarization of particles with respect to the suspending medium is expressed in terms of the Clausius-Mossotti factor, a parameter of crucial importance in dielectrophoretic-based operations. Particle relative polarization was studied by employing insulator-based dielectrophoretic (iDEP) devices. The effects of particle size, medium conductivity, and frequency (10-1000 Hz) of the applied electric potential on particle response were assessed through experiments and mathematical modeling with COMSOL Multiphysics(®). Particles of different sizes (100-1000 nm diameters) were introduced into iDEP devices fabricated from polydimethylsiloxane (PDMS) and their dielectrophoretic responses under direct and alternating current electric fields were recorded and analyzed in the form of images and videos. The results illustrated that particle polarizability and dielectrophoretic response depend greatly on particle size and the frequency of the electric field. Small particles tend to exhibit positive DEP at higher frequencies (200-1000 Hz), while large particles exhibit negative DEP at lower frequencies (20-200 Hz). These differences in relative polarization can be used for the design of iDEP-based separations and analysis of particle mixtures.
Collapse
Affiliation(s)
| | - Mallory M Rauch
- Microscale Bioseparations Laboratory, Rochester Institute of Technology, Rochester, NY, USA
| | - Alexandra LaLonde
- Microscale Bioseparations Laboratory, Rochester Institute of Technology, Rochester, NY, USA
| | | |
Collapse
|
41
|
Silver Nanoparticles Decrease the Viability of Cryptosporidium parvum Oocysts. Appl Environ Microbiol 2015; 82:431-7. [PMID: 26497464 DOI: 10.1128/aem.02806-15] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 10/12/2015] [Indexed: 11/20/2022] Open
Abstract
Oocysts of the waterborne protozoan parasite Cryptosporidium parvum are highly resistant to chlorine disinfection. We show here that both silver nanoparticles (AgNPs) and silver ions significantly decrease oocyst viability, in a dose-dependent manner, between concentrations of 0.005 and 500 μg/ml, as assessed by an excystation assay and the shell/sporozoite ratio. For percent excystation, the results are statistically significant for 500 μg/ml of AgNPs, with reductions from 83% for the control to 33% with AgNPs. For Ag ions, the results were statistically significant at 500 and 5,000 μg/ml, but the percent excystation values were reduced only to 66 and 62%, respectively, from 86% for the control. The sporozoite/shell ratio was affected to a greater extent following AgNP exposure, presumably because sporozoites are destroyed by interaction with NPs. We also demonstrated via hyperspectral imaging that there is a dual mode of interaction, with Ag ions entering the oocyst and destroying the sporozoites while AgNPs interact with the cell wall and, at high concentrations, are able to fully break the oocyst wall.
Collapse
|
42
|
Challenges and Innovative Strategies to Interrupt Cryptosporidium Transmission in Resource-Limited Settings. CURRENT TROPICAL MEDICINE REPORTS 2015. [DOI: 10.1007/s40475-015-0057-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
43
|
Destura RV, Cena RB, Galarion MJH, Pangilinan CM, Arevalo GM, Alba ROC, Petronio JAG, Salem GM, Schwem B, Sevilleja JEAD. Advancing Cryptosporidium Diagnostics from Bench to Bedside. CURRENT TROPICAL MEDICINE REPORTS 2015. [DOI: 10.1007/s40475-015-0055-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
44
|
Allahrabbi N, Chia YSM, Saifullah MSM, Lim KM, Yung LYL. A hybrid dielectrophoretic system for trapping of microorganisms from water. BIOMICROFLUIDICS 2015; 9:034110. [PMID: 26180567 PMCID: PMC4474952 DOI: 10.1063/1.4922276] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/28/2015] [Indexed: 05/24/2023]
Abstract
Assessment of the microbial safety of water resources is among the most critical issues in global water safety. As the current detection methods have limitations such as high cost and long process time, new detection techniques have transpired among which microfluidics is the most attractive alternative. Here, we show a novel hybrid dielectrophoretic (DEP) system to separate and detect two common waterborne pathogens, Escherichia coli (E. coli), a bacterium, and Cryptosporidium parvum (C. parvum), a protozoan parasite, from water. The hybrid DEP system integrates a chemical surface coating with a microfluidic device containing inter-digitated microelectrodes to impart positive dielectrophoresis for enhanced trapping of the cells. Trimethoxy(3,3,3-trifluoropropyl) silane, (3-aminopropyl)triethoxysilane, and polydiallyl dimethyl ammonium chloride (p-DADMAC) were used as surface coatings. Static cell adhesion tests showed that among these coatings, the p-DADMAC-coated glass surface provided the most effective cell adhesion for both the pathogens. This was attributed to the positively charged p-DADMAC-coated surface interacting electrostatically with the negatively charged cells suspended in water leading to increased cell trapping efficiency. The trapping efficiency of E. coli and C. parvum increased from 29.0% and 61.3% in an uncoated DEP system to 51.9% and 82.2% in the hybrid DEP system, respectively. The hybrid system improved the cell trapping by encouraging the formation of cell pearl-chaining. The increment in trapping efficiency in the hybrid DEP system was achieved at an optimal frequency of 1 MHz and voltage of 2.5 Vpp for C. parvum and 2 Vpp for E. coli, the latter is lower than 2.5 Vpp and 7 Vpp, respectively, utilized for obtaining similar efficiency in an uncoated DEP system.
Collapse
Affiliation(s)
| | - Yi Shi Michelle Chia
- Department of Chemical and Biomolecular Engineering, National University of Singapore , 10 Kent Ridge Crescent, Singapore 119260, Republic of Singapore
| | - Mohammad S M Saifullah
- Institute of Materials Research and Engineering , ASTAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Republic of Singapore
| | - Kian-Meng Lim
- Department of Mechanical Engineering, National University of Singapore , 9 Engineering Drive 1, Singapore 117576, Republic of Singapore
| | - Lin Yue Lanry Yung
- Department of Chemical and Biomolecular Engineering, National University of Singapore , 10 Kent Ridge Crescent, Singapore 119260, Republic of Singapore
| |
Collapse
|
45
|
Ehdaie B, Krause C, Smith JA. Porous ceramic tablet embedded with silver nanopatches for low-cost point-of-use water purification. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:13901-13908. [PMID: 25387099 DOI: 10.1021/es503534c] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This work describes a novel method to embed silver in ceramic porous media in the form of metallic silver nanopatches. This method has been applied to develop a new POU technology, a silver-infused ceramic tablet that provides long-term water disinfection. The tablet is fabricated using clay, water, sawdust, and silver nitrate. When dropped into a household water storage container, the ceramic tablet releases silver ions at a controlled rate that in turn disinfect microbial pathogens. Characterization of the silver-embedded ceramic media was performed using transmission electron microscopy. Spherical-shaped patches of metallic silver were observed at 1–6 nm diameters and confirmed to be silver with energy dispersive spectroscopy. Disinfection experiments in a 10 L water volume demonstrated a 3 log reduction of Escherichia coli within 8 h while silver levels remained below the World Health Organization drinking water standard (0.1 mg/L). Silver release rate varied with clay mineralogy, sawdust particle size, and initial silver mass. Silver release was repeatable for daily 10 L volumes for 154 days. Results suggest the ceramic tablet can be used to treat a range of water volumes. This technology shows great potential to be a low-cost, simple-to-use water treatment method to provide microbiologically safe drinking water at the household level.
Collapse
Affiliation(s)
- Beeta Ehdaie
- Department of Civil and Environmental Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
| | | | | |
Collapse
|
46
|
Zellner P, Shake T, Hosseini Y, Nakidde D, Riquelme MV, Sahari A, Pruden A, Behkam B, Agah M. 3D Insulator-based dielectrophoresis using DC-biased, AC electric fields for selective bacterial trapping. Electrophoresis 2014; 36:277-83. [DOI: 10.1002/elps.201400236] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 09/10/2014] [Accepted: 09/17/2014] [Indexed: 11/07/2022]
Affiliation(s)
- Phillip Zellner
- VT MEMS Laboratory; Bradley Department of Electrical and Computer Engineering; Virginia Tech; Blacksburg VA USA
| | - Tyler Shake
- VT MEMS Laboratory; Bradley Department of Electrical and Computer Engineering; Virginia Tech; Blacksburg VA USA
| | - Yahya Hosseini
- VT MEMS Laboratory; Bradley Department of Electrical and Computer Engineering; Virginia Tech; Blacksburg VA USA
| | - Diana Nakidde
- VT MEMS Laboratory; Bradley Department of Electrical and Computer Engineering; Virginia Tech; Blacksburg VA USA
| | - Maria V. Riquelme
- The Charles E. Via; Jr. Department of Civil and Environmental Engineering; Virginia Tech; Blacksburg VA USA
| | - Ali Sahari
- MicroN Base Laboratory; Department of Mechanical Engineering; Virginia Tech; Blacksburg VA USA
| | - Amy Pruden
- The Charles E. Via; Jr. Department of Civil and Environmental Engineering; Virginia Tech; Blacksburg VA USA
| | - Bahareh Behkam
- MicroN Base Laboratory; Department of Mechanical Engineering; Virginia Tech; Blacksburg VA USA
| | - Masoud Agah
- VT MEMS Laboratory; Bradley Department of Electrical and Computer Engineering; Virginia Tech; Blacksburg VA USA
| |
Collapse
|
47
|
Farmehini V, Rohani A, Su YH, Swami NS. A wide-bandwidth power amplifier for frequency-selective insulator-based dielectrophoresis. LAB ON A CHIP 2014; 14:4183-7. [PMID: 25226875 DOI: 10.1039/c4lc00801d] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Insulator-based dielectrophoresis enables contact-less separation and analysis of biosystems, but it is unable to operate effectively in the MHz frequency range, which is necessary for the manipulation of biological cells based on the characteristic electrophysiology of their cytoplasm or biomolecular preconcentration based on their unique conformation. To address the steep drop in output power and the rise of signal distortions within conventional amplifiers at MHz frequencies due to slew rate limitations, we present the design principles for a wideband amplifier. This is validated by demonstrating the absence of harmonic distortions and parasitic DC within the amplifier output up to 15 MHz, thereby enabling analysis of cytoplasmic alterations on oocysts of Cryptosporidium parvum, due to constant force dispersion in the MHz range.
Collapse
Affiliation(s)
- Vahid Farmehini
- Department of Electrical & Computer Engineering, University of Virginia, Charlottesville, VA 22904, USA.
| | | | | | | |
Collapse
|
48
|
Su YH, Warren CA, Guerrant R, Swami NS. Dielectrophoretic monitoring and interstrain separation of intact Clostridium difficile based on their S(Surface)-layers. Anal Chem 2014; 86:10855-63. [PMID: 25343746 PMCID: PMC4222627 DOI: 10.1021/ac5029837] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Accepted: 10/09/2014] [Indexed: 12/16/2022]
Abstract
Clostridium difficile (C. difficile) infection (CDI) rates have exhibited a steady rise worldwide over the last two decades and the infection poses a global threat due to the emergence of antibiotic resistant strains. Interstrain antagonistic interactions across the host microbiome form an important strategy for controlling the emergence of CDI. The current diagnosis method for CDI, based on immunoassays for toxins produced by pathogenic C. difficile strains, is limited by false negatives due to rapid toxin degradation. Furthermore, simultaneous monitoring of nontoxigenic C. difficile strains is not possible, due to absence of these toxins, thereby limiting its application toward the control of CDI through optimizing antagonistic interstrain interactions. Herein, we demonstrate that morphological differences within the cell wall of particular C. difficile strains with differing S-layer proteins can induce systematic variations in their electrophysiology, due alterations in cell wall capacitance. As a result, dielectrophoretic frequency analysis can enable the independent fingerprinting and label-free separation of intact microbials of each strain type from mixed C. difficile samples. The sensitivity of this contact-less electrophysiological method is benchmarked against the immunoassay and microbial growth rate methods for detecting alterations within both, toxigenic and nontoxigenic C. difficile strains after vancomycin treatment. This microfluidic diagnostic platform can assist in the development of therapies for arresting clostridial infections by enabling the isolation of individual strains, optimization of antibiotic treatments and the monitoring of microbiomes.
Collapse
Affiliation(s)
- Yi-Hsuan Su
- Electrical
and Computer Engineering, University of
Virginia at Thornton Hall, 351 McCormick Road, P.O. Box 400743, Charlottesville, Virginia 22904, United States
| | - Cirle A. Warren
- Infectious
Diseases, School of Medicine, University
of Virginia at Infectious Diseases & International Health, P.O. Box 801379, Charlottesville, Virginia 22908, United
States
| | - Richard
L. Guerrant
- Infectious
Diseases, School of Medicine, University
of Virginia at Infectious Diseases & International Health, P.O. Box 801379, Charlottesville, Virginia 22908, United
States
| | - Nathan S. Swami
- Electrical
and Computer Engineering, University of
Virginia at Thornton Hall, 351 McCormick Road, P.O. Box 400743, Charlottesville, Virginia 22904, United States
| |
Collapse
|
49
|
Rohani A, Varhue W, Su YH, Swami NS. Quantifying spatio-temporal dynamics of biomarker pre-concentration and depletion in microfluidic systems by intensity threshold analysis. BIOMICROFLUIDICS 2014; 8:052009. [PMID: 25538800 PMCID: PMC4222295 DOI: 10.1063/1.4897283] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 09/25/2014] [Indexed: 05/05/2023]
Abstract
Microfluidic systems are commonly applied towards pre-concentration of biomarkers for enhancing detection sensitivity. Quantitative information on the spatial and temporal dynamics of pre-concentration, such as its position, extent, and time evolution are essential towards sensor design for coupling pre-concentration to detection. Current quantification methodologies are based on the time evolution of fluorescence signals from biomarkers within a statically defined region of interest, which does not offer information on the spatial dynamics of pre-concentration and leads to significant errors when the pre-concentration zone is delocalized or exhibits wide variations in size, shape, and position over time under the force field. We present a dynamic methodology for quantifying the region of interest by using a statistical description of particle distribution across the device geometry to determine the intensity thresholds for particle pre-concentration. This method is applied to study the delocalized pre-concentration dynamics under an electrokinetic force balance driven by negative dielectrophoresis, for aligning the pre-concentration and detection regions of neuropeptide Y, and for quantifying the polarizability dispersion of silica nano-colloids with frequency of the force field. We envision the application of this automated methodology on data from 2D images and 3D Z-stacks for quantifying pre-concentration dynamics over delocalized regions as a function of the force field.
Collapse
Affiliation(s)
- Ali Rohani
- Electrical and Computer Engineering, University of Virginia , Charlottesville, Virginia 22904, USA
| | - Walter Varhue
- Electrical and Computer Engineering, University of Virginia , Charlottesville, Virginia 22904, USA
| | - Yi-Hsuan Su
- Electrical and Computer Engineering, University of Virginia , Charlottesville, Virginia 22904, USA
| | - Nathan S Swami
- Electrical and Computer Engineering, University of Virginia , Charlottesville, Virginia 22904, USA
| |
Collapse
|
50
|
Dash S, Mohanty S. Dielectrophoretic separation of micron and submicron particles: a review. Electrophoresis 2014; 35:2656-72. [PMID: 24930837 DOI: 10.1002/elps.201400084] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 06/03/2014] [Accepted: 06/05/2014] [Indexed: 11/06/2022]
Abstract
This paper provides an overview on separation of micron and submicron sized biological (cells, yeast, virus, bacteria, etc.) and nonbiological particles (latex, polystyrene, CNTs, metals, etc.) by dielectrophoresis (DEP), which finds wide applications in the field of medical and environmental science. Mathematical models to predict the electric field, flow profile, and concentration profiles of the particles under the influence of DEP force have also been covered in this review. In addition, advancements made primarily in the last decade, in the area of electrode design (shape and arrangement), new materials for electrode (carbon, silicon, polymers), and geometry of the microdevice, for efficient DEP separation of particles have been highlighted.
Collapse
Affiliation(s)
- Swagatika Dash
- CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, India
| | | |
Collapse
|