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Luo X, Li W, Liang Z, Liu Y, Fan DE. Portable Bulk-Water Disinfection by Live Capture of Bacteria with Divergently Branched Porous Graphite in Electric Fields. ACS NANO 2023. [PMID: 37224419 DOI: 10.1021/acsnano.2c12229] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Easy access to clean water is essential to functioning and development of modern society. However, it remains arduous to develop energy-efficient, facile, and portable water treatment systems for point-of-use (POU) applications, which is particularly imperative for the safety and resilience of society during extreme weather and critical situations. Here, we propose and validate a meritorious working scheme for water disinfection via directly capturing and removing pathogen cells from bulk water using strategically designed three-dimensional (3D) porous dendritic graphite foams (PDGFs) in a high-frequency AC field. The prototype, integrated in a 3D-printed portable water-purification module, can reproducibly remove 99.997% E. coli bacteria in bulk water at a few voltages with among the lowest energy consumption at 435.5 J·L-1. The PDGFs, costing $1.47 per piece, can robustly operate at least 20 times for more than 8 h in total without functional degradation. Furthermore, we successfully unravel the involved disinfection mechanism with one-dimensional Brownian dynamics simulation. The system is practically applied that brings natural water in Waller Creek at UT Austin to the safe drinking level. This research, including the working mechanism based on dendritically porous graphite and the design scheme, could inspire a future device paradigm for POU water treatment.
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2
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Boika A. On Practical Aspects of Single-Entity Electrochemical Measurements with Hot Microelectrodes. Anal Chem 2023; 95:4577-4584. [PMID: 36862018 DOI: 10.1021/acs.analchem.2c03978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
When a 10s-100s MHz frequency alternating current (ac) waveform is applied to a disk ultramicroelectrode (UME) in an electrochemical cell, one achieves what is known as a hot microelectrode, or a hot UME. The electrical energy generates heat in an electrolyte solution surrounding the electrode, and the heat transfer leads to formation of a hot zone with the size comparable to the electrode diameter. In addition to heating, ac electrokinetic phenomena generated by the waveform include dielectrophoresis (DEP) and electrothermal fluid flow (ETF). These phenomena can be harvested to manipulate the motion of analyte species and achieve significant improvements in their single-entity electrochemical (SEE) detection. This work evaluates various microscale forces observable with hot UMEs in relation to their utility to improve the sensitivity and specificity of the SEE analysis. Considering only mild heating (with a UME temperature increase not exceeding 10 K), the sensitivity of the SEE detection of metal nanoparticles and bacterial (Staph. aureus) species is shown to be strongly affected by the DEP and ETF phenomena. The conditions have been identified, such as the ac frequency and supporting electrolyte concentration, that can lead to orders-of-magnitude enhancement of the frequency of analyte collisions with a hot UME. In addition, even mild heating is expected to result in up to four times increase in the magnitude of blocking collisions' current steps, with similar outcomes expected for electrocatalytic collisional systems. The findings presented here are thought to provide guidance to researchers wishing to adopt hot UME technology for SEE analysis. With many possibilities still open, the future of such a combined approach is expected to be bright.
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Affiliation(s)
- Aliaksei Boika
- Department of Chemistry, University of Akron, Akron, Ohio 44325, United States
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3
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Stanke S, Wenger C, Bier FF, Hölzel R. AC electrokinetic immobilization of influenza virus. Electrophoresis 2022; 43:1309-1321. [DOI: 10.1002/elps.202100324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 12/26/2021] [Accepted: 01/06/2022] [Indexed: 11/05/2022]
Affiliation(s)
- Sandra Stanke
- Fraunhofer Institute for Cell Therapy and Immunology Branch Bioanalytics and Bioprocesses (IZI‐BB) Potsdam‐Golm Germany
- Institute of Biochemistry and Biology University of Potsdam Potsdam‐Golm Germany
| | - Christian Wenger
- IHP – Leibnizinstitut für innovative Mikroelektronik Frankfurt/Oder Germany
- Brandenburg University of Technology Cottbus–Senftenberg Cottbus Germany
| | - Frank F. Bier
- Institute of Biochemistry and Biology University of Potsdam Potsdam‐Golm Germany
| | - Ralph Hölzel
- Fraunhofer Institute for Cell Therapy and Immunology Branch Bioanalytics and Bioprocesses (IZI‐BB) Potsdam‐Golm Germany
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4
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Experimental Verification of Dielectric Models with a Capacitive Wheatstone Bridge Biosensor for Living Cells: E. coli. SENSORS 2022; 22:s22072441. [PMID: 35408055 PMCID: PMC9002767 DOI: 10.3390/s22072441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/14/2022] [Accepted: 03/19/2022] [Indexed: 12/10/2022]
Abstract
Detection of bioparticles is of great importance in electrophoresis, identification of biomass sources, food and water safety, and other areas. It requires a proper model to describe bioparticles' electromagnetic characteristics. A numerical study of Escherichia coli bacteria during their functional activity was carried out by using two different geometrical models for the cells that considered the bacteria as layered ellipsoids and layered spheres. It was concluded that during cell duplication, the change in the dielectric permittivity of the cell is high enough to be measured at radio frequencies of the order of 50 kHz. An experimental setup based on the capacitive Wheatstone bridge was designed to measure relative changes in permittivity during cell division. In this way, the theoretical model was validated by measuring the dielectric permittivity changes in a cell culture of Escherichia coli ATTC 8739 from WDCM 00012 Vitroids. The spheroidal model was confirmed to be more accurate.
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5
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Jain MC, Nadaraja AV, Narang R, Zarifi MH. Rapid and real-time monitoring of bacterial growth against antibiotics in solid growth medium using a contactless planar microwave resonator sensor. Sci Rep 2021; 11:14775. [PMID: 34285253 PMCID: PMC8292355 DOI: 10.1038/s41598-021-94139-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 07/05/2021] [Indexed: 11/10/2022] Open
Abstract
Infection diagnosis and antibiotic susceptibility testing (AST) are pertinent clinical microbiology practices that are in dire need of improvement, due to the inadequacy of current standards in early detection of bacterial response to antibiotics and affordability of contemporarily used methods. This paper presents a novel way to conduct AST which hybridizes disk diffusion AST with microwave resonators for rapid, contactless, and non-invasive sensing and monitoring. In this research, the effect of antibiotic (erythromycin) concentrations on test bacterium, Escherichia coli (E. coli) cultured on solid agar medium (MH agar) are monitored through employing a microwave split-ring resonator. A one-port microwave resonator operating at a 1.76 GHz resonant frequency, featuring a 5 mm2 sensitive sensing region, was designed and optimized to perform this. Upon introducing uninhibited growth of the bacteria, the sensor measured 0.005 dB/hr, with a maximum change of 0.07 dB over the course of 15 hours. The amplitude change decreased to negligible values to signify inhibited growth of the bacteria at higher concentrations of antibiotics, such as a change of 0.005 dB in resonant amplitude variation while using 45 µg of antibiotic. Moreover, this sensor demonstrated decisive results of antibiotic susceptibility in under 6 hours and shows great promise to expand automation to the intricate AST workflow in clinical settings, while providing rapid, sensitive, and non-invasive detection capabilities.
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Affiliation(s)
- Mandeep Chhajer Jain
- Okanagan Microelectronics and Gigahertz Applications Laboratory, School of Engineering, University of British Columbia, Kelowna, BC, V1V 1V7, Canada
| | - Anupama Vijaya Nadaraja
- Okanagan Microelectronics and Gigahertz Applications Laboratory, School of Engineering, University of British Columbia, Kelowna, BC, V1V 1V7, Canada
| | - Rakesh Narang
- Okanagan Microelectronics and Gigahertz Applications Laboratory, School of Engineering, University of British Columbia, Kelowna, BC, V1V 1V7, Canada
| | - Mohammad Hossein Zarifi
- Okanagan Microelectronics and Gigahertz Applications Laboratory, School of Engineering, University of British Columbia, Kelowna, BC, V1V 1V7, Canada.
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6
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Perez‐Gonzalez VH. Particle trapping in electrically driven insulator-based microfluidics: Dielectrophoresis and induced-charge electrokinetics. Electrophoresis 2021; 42:2445-2464. [PMID: 34081787 PMCID: PMC9291494 DOI: 10.1002/elps.202100123] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/29/2021] [Accepted: 06/01/2021] [Indexed: 12/31/2022]
Abstract
Electrokinetically driven insulator‐based microfluidic devices represent an attractive option to manipulate particle suspensions. These devices can filtrate, concentrate, separate, or characterize micro and nanoparticles of interest. Two decades ago, inspired by electrode‐based dielectrophoresis, the concept of insulator‐based dielectrophoresis (iDEP) was born. In these microfluidic devices, insulating structures (i.e., posts, membranes, obstacles, or constrictions) built within the channel are used to deform the spatial distribution of an externally generated electric field. As a result, particles suspended in solution experience dielectrophoresis (DEP). Since then, it has been assumed that DEP is responsible for particle trapping in these devices, regardless of the type of voltage being applied to generate the electric field—direct current (DC) or alternating current. Recent findings challenge this assumption by demonstrating particle trapping and even particle flow reversal in devices that prevent DEP from occurring (i.e., unobstructed long straight channels stimulated with a DC voltage and featuring a uniform electric field). The theory introduced to explain those unexpected observations was then applied to conventional “DC‐iDEP” devices, demonstrating better prediction accuracy than that achieved with the conventional DEP‐centered theory. This contribution summarizes contributions made during the last two decades, comparing both theories to explain particle trapping and highlighting challenges to address in the near future.
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7
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Zhang F, Wang S, Yang Y, Jiang J, Tao N. Imaging Single Bacterial Cells with Electro-optical Impedance Microscopy. ACS Sens 2021; 6:348-354. [PMID: 32456424 DOI: 10.1021/acssensors.0c00751] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Impedance measurements have been an important tool for biosensor applications, including protein detection, DNA quantification, and cell study. We present here an electro-optical impedance microscopy (EIM) based on the dependence of surface optical transmission on local surface charge density for single bacteria impedance imaging. We applied a potential modulation to bacteria placed on an indium tin oxide-coated slide and simultaneously recorded a sequence of transmitted microscopy images. By performing fast Fourier transform analysis on the image sequences, we obtained the DC component (signal at 0 Hz) for cell morphology imaging and the AC component (signal at the modulation frequency) for the mapping of cell impedance responses with subcellular resolution for the first time. Using this method, we have monitored the viability of Escherichia coli bacterial cells under treatment with two different classes of antibiotics with low-frequency potential modulation. The results showed that the impedance response is sensitive to the antibiotic that targets the bacterial cell membrane as the membrane capacitance dominated at low-frequency modulation. Heterogeneous responses to the antibiotic treatment were observed at a single bacteria level. In addition to the high spatial resolution, EIM is label-free and simple and can be potentially used for the continuous mapping of single bacteria impedance changes under different conditions.
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Affiliation(s)
- Fenni Zhang
- Biodesign Center for Bioelectronics and Biosensors, Arizona State University, Tempe, Arizona 85287-5801, United States
| | - Shaopeng Wang
- Biodesign Center for Bioelectronics and Biosensors, Arizona State University, Tempe, Arizona 85287-5801, United States
| | - Yunze Yang
- Biodesign Center for Bioelectronics and Biosensors, Arizona State University, Tempe, Arizona 85287-5801, United States
| | - Jiapei Jiang
- Biodesign Center for Bioelectronics and Biosensors, Arizona State University, Tempe, Arizona 85287-5801, United States
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287, United States
| | - Nongjian Tao
- Biodesign Center for Bioelectronics and Biosensors, Arizona State University, Tempe, Arizona 85287-5801, United States
- School of Electrical Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287, United States
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8
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Jain MC, Nadaraja AV, Mohammadi S, Vizcaino BM, Zarifi MH. Passive Microwave Biosensor for Real-Time Monitoring of Subsurface Bacterial Growth. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2021; 15:122-132. [PMID: 33513106 DOI: 10.1109/tbcas.2021.3055227] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A real-time and label-free microstrip sensor capable of detecting and monitoring subsurface growth of Escherichia coli (E. coli) on solid growth media such as Luria-Bertani (LB) agar is presented. The microwave ring resonator was designed to operate at 1.76 GHz to detect variations in the dielectric properties such as permittivity and loss tangent to monitor bacterial growth. The sensor demonstrated high efficiency in monitoring subsurface dynamics of E. coli growth between two layers of LB agar. The resonant amplitude variations (Δ Amplitude (dB)) were recorded for different volumes of E. coli (3 μL and 9 μL) and compared to control without E. coli for 36 hours. The control showed a maximum amplitude variation of 0.037 dB, which was selected as a threshold to distinguish between the presence and absence of E. coli growth. The measured results by sensors were further supported by microscopic images. It is worth noticing that the amplitude variations fit well with the Gompertz growth model. The rate of amplitude change correlating bacteria growth rate was calculated as 0.08 and 0.13 dB/hr. for 3 μL and 9 μL of E. coli, respectively. This work is a proof of concept to demonstrate the capability of microwave sensors to detect and monitor subsurface bacterial growth.
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9
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Han CH, Jang J. Integrated microfluidic platform with electrohydrodynamic focusing and a carbon-nanotube-based field-effect transistor immunosensor for continuous, selective, and label-free quantification of bacteria. LAB ON A CHIP 2021; 21:184-195. [PMID: 33283832 DOI: 10.1039/d0lc00783h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Electrokinetic technologies such as AC electro-osmosis (EO) and dielectrophoresis (DEP) have been used for effective manipulation of bacteria to enhance the sensitivity of an assay, and many previously reported electrokinetics-enhanced biosensors are based on stagnant fluids. An effective region for positive DEP for particle capture is usually too close to the electrode for the flowing particles to move toward the detection zone of a biosensor against the flow direction; this poses a technical challenge for electrokinetics-assisted biosensors implemented within pressure-driven flows, especially if the particles flow with high speed and if the detection zone is small. Here, we present a microfluidic single-walled carbon nanotube (SWCNT)-based field-effect transistor immunosensor with electrohydrodynamic (EHD) focusing and DEP concentration for continuous and label-free detection of flowing Staphylococcus aureus in a 0.01× phosphate buffered saline (PBS) solution. The EHD focusing involved AC EO and negative DEP to align the flowing particles along lines close to the bottom surface of a microfluidic channel for facilitating particle capture downstream at the detection zone. For feasibility, 380 nm-diameter fluorescent beads suspended in 0.001× PBS were tested, and 14.6 times more beads were observed to be concentrated in the detection area with EHD focusing. Moreover, label-free, continuous, and selective measurement of S. aureus in 0.01× PBS was demonstrated, showing good linearity between the relative changes in electrical conductance of the SWCNTs and logarithmic S. aureus concentrations, a capture/detection time of 35 min, and a limit of detection of 150 CFU mL-1, as well as high specificity through electrical manipulation and biological interaction.
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Affiliation(s)
- Chang-Ho Han
- Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.
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10
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Çağlayan Z, Demircan Yalçın Y, Külah H. A Prominent Cell Manipulation Technique in BioMEMS: Dielectrophoresis. MICROMACHINES 2020; 11:E990. [PMID: 33153069 PMCID: PMC7693018 DOI: 10.3390/mi11110990] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/22/2020] [Accepted: 10/28/2020] [Indexed: 12/17/2022]
Abstract
BioMEMS, the biological and biomedical applications of micro-electro-mechanical systems (MEMS), has attracted considerable attention in recent years and has found widespread applications in disease detection, advanced diagnosis, therapy, drug delivery, implantable devices, and tissue engineering. One of the most essential and leading goals of the BioMEMS and biosensor technologies is to develop point-of-care (POC) testing systems to perform rapid prognostic or diagnostic tests at a patient site with high accuracy. Manipulation of particles in the analyte of interest is a vital task for POC and biosensor platforms. Dielectrophoresis (DEP), the induced movement of particles in a non-uniform electrical field due to polarization effects, is an accurate, fast, low-cost, and marker-free manipulation technique. It has been indicated as a promising method to characterize, isolate, transport, and trap various particles. The aim of this review is to provide fundamental theory and principles of DEP technique, to explain its importance for the BioMEMS and biosensor fields with detailed references to readers, and to identify and exemplify the application areas in biosensors and POC devices. Finally, the challenges faced in DEP-based systems and the future prospects are discussed.
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Affiliation(s)
- Zeynep Çağlayan
- Department of Electrical and Electronics Engineering, Middle East Technical University, Ankara 06800, Turkey; (Z.Ç.); (Y.D.Y.)
- METU MEMS Research and Application Center, Ankara 06800, Turkey
| | - Yağmur Demircan Yalçın
- Department of Electrical and Electronics Engineering, Middle East Technical University, Ankara 06800, Turkey; (Z.Ç.); (Y.D.Y.)
- Mikro Biyosistemler Electronics Inc., Ankara 06530, Turkey
| | - Haluk Külah
- Department of Electrical and Electronics Engineering, Middle East Technical University, Ankara 06800, Turkey; (Z.Ç.); (Y.D.Y.)
- METU MEMS Research and Application Center, Ankara 06800, Turkey
- Mikro Biyosistemler Electronics Inc., Ankara 06530, Turkey
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11
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Lee M, Won JB, Jung DH, Kim J, Choi Y, Akyildiz K, Choi J, Kim K, Cho J, Yoon H, Koo HJ. Dielectrophoretic Manipulation of Janus Particle in Conductive Media for Biomedical Applications. Biotechnol J 2020; 15:e2000343. [PMID: 33067912 DOI: 10.1002/biot.202000343] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 10/14/2020] [Indexed: 01/07/2023]
Abstract
Janus particles are applied to many fields including biomedical applications. To expand the usability of Janus particles, a technique to manipulate the particle movement is required. A dielectrophoresis (DEP) method can be a promising candidate; however, independent manipulation or separation of Janus particle by DEP is still challenging. Additionally, DEP of Janus particles in conductive media is important especially for biomedical applications where ion-rich media are typically used. Here, the experimental results of DEP-induced transport and separation of the Janus particle in conductive media are presented. To predict the DEP behavior, the Clausius-Mossotti (CM) factors of both Janus and homogeneous particles are calculated, depending on the alternating current (AC) frequency and medium conductivity. The Janus particles show the positive-DEP behavior at the entire AC frequency region tested due to the metal-coated half surface. On the other hand, the homogeneous particles show the negative-DEP behavior at the high AC frequency or in conductive media. Additionally, in the conductive media, an electrohydrodynamic flow hinders the DEP-driven particle transport below MHz AC frequencies. Finally, the separation of the Janus particles from the homogeneous ones is experimentally demonstrated and the separation efficiency is discussed based on the evaluation parameters established in this study.
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Affiliation(s)
- Minji Lee
- Department of Chemical and Biomolecular Engineering, Seoul National University of Science and Technology, 232 Gongneung-ro, Seoul, 01811, Republic of Korea
| | - Jong Bin Won
- Department of Chemical and Biomolecular Engineering, Seoul National University of Science and Technology, 232 Gongneung-ro, Seoul, 01811, Republic of Korea
| | - Dae Ho Jung
- Department of Chemical and Biomolecular Engineering, Seoul National University of Science and Technology, 232 Gongneung-ro, Seoul, 01811, Republic of Korea
| | - Jaekyoung Kim
- Department of Chemical and Biomolecular Engineering, Seoul National University of Science and Technology, 232 Gongneung-ro, Seoul, 01811, Republic of Korea
| | - Yonghyun Choi
- School of Integrative Engineering, Chung-Ang University, 84 Heukseok-ro, Seoul, 06974, Republic of Korea
| | - Kubra Akyildiz
- Department of Chemical and Biomolecular Engineering, Seoul National University of Science and Technology, 232 Gongneung-ro, Seoul, 01811, Republic of Korea
| | - Jonghoon Choi
- School of Integrative Engineering, Chung-Ang University, 84 Heukseok-ro, Seoul, 06974, Republic of Korea
| | - Kyobum Kim
- Department of Chemical and Biochemical Engineering, Dongguk University, Pildong-ro 1-gil, Seoul, 04620, Republic of Korea
| | - Jiung Cho
- Western Seoul Center, Korea Basic Science Institute, 150 Bugahyeon-ro, Seoul, 03759, Republic of Korea
| | - Hyunsik Yoon
- Department of Chemical and Biomolecular Engineering, Seoul National University of Science and Technology, 232 Gongneung-ro, Seoul, 01811, Republic of Korea
| | - Hyung-Jun Koo
- Department of Chemical and Biomolecular Engineering, Seoul National University of Science and Technology, 232 Gongneung-ro, Seoul, 01811, Republic of Korea
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12
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Henslee EA. Review: Dielectrophoresis in cell characterization. Electrophoresis 2020; 41:1915-1930. [DOI: 10.1002/elps.202000034] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 05/31/2020] [Accepted: 07/14/2020] [Indexed: 12/23/2022]
Affiliation(s)
- Erin A. Henslee
- Department of Engineering Wake Forest University 455 Vine St. Winston‐Salem USA
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13
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Epping MS, Wedde S, Grundmann A, Radukic M, Gröger H, Hummel A, Viefhues M. Dielectrophoretic analysis of the impact of isopropyl alcohol on the electric polarisability of Escherichia coli whole-cells. Anal Bioanal Chem 2020; 412:3925-3933. [PMID: 32157360 PMCID: PMC7235074 DOI: 10.1007/s00216-020-02451-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/13/2020] [Accepted: 01/23/2020] [Indexed: 12/18/2022]
Abstract
Whole-cell biocatalysts are versatile tools in (industrial) production processes; though, the effects that impact the efficiency are not fully understood yet. One main factor that affects whole-cell biocatalysts is the surrounding medium, which often consists of organic solvents due to low solubility of substrates in aqueous solutions. It is expected that organic solvents change the biophysical and biochemical properties of the whole-cell biocatalysts, e.g. by permeabilising the cell membrane, and thus analysis of these effects is of high importance. In this work, we present an analysis method to study the impact of organic solvents on whole-cell biocatalysts by means of dielectrophoresis. For instance, we evaluate the changes of the characteristic dielectrophoretic trapping ratio induced by incubation of Escherichia coli, serving as a model system, in an aqueous medium containing isopropyl alcohol. Therefore, we could evaluate the impact on the electric polarisability of the cells. For this purpose, a special microchannel device was designed and Escherichia coli cells were genetically modified to reliably synthesise a green fluorescent protein. We could demonstrate that our method was capable of revealing different responses to small changes in isopropyl alcohol concentration and incubation duration. Complementary spectrophotometric UV-Vis (ultraviolet-visible light) absorbance analysis of released NAD(P)+/NAD(P)H cofactor and proteins confirmed our results. Based on our results, we discuss the biophysical effects taking place during incubation. Graphical abstract.
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Affiliation(s)
- Miriam S Epping
- Experimental Biophysics and Applied Nanosciences, Department of Physics, Bielefeld University, 33615, Bielefeld, Germany
| | - Severin Wedde
- Industrial Organic Chemistry and Biotechnology, Department of Chemistry, Bielefeld University, 33615, Bielefeld, Germany
- Fermentation Engineering, Department of Technology, Bielefeld University, 33615, Bielefeld, Germany
| | - Armin Grundmann
- Experimental Biophysics and Applied Nanosciences, Department of Physics, Bielefeld University, 33615, Bielefeld, Germany
| | - Marco Radukic
- Experimental Biophysics and Applied Nanosciences, Department of Physics, Bielefeld University, 33615, Bielefeld, Germany
- Cellular and Molecular Biotechnology, Department of Technology, Bielefeld University, 33615, Bielefeld, Germany
| | - Harald Gröger
- Industrial Organic Chemistry and Biotechnology, Department of Chemistry, Bielefeld University, 33615, Bielefeld, Germany
| | - Anke Hummel
- Industrial Organic Chemistry and Biotechnology, Department of Chemistry, Bielefeld University, 33615, Bielefeld, Germany
| | - Martina Viefhues
- Experimental Biophysics and Applied Nanosciences, Department of Physics, Bielefeld University, 33615, Bielefeld, Germany.
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14
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Liang W, Yang X, Wang J, Wang Y, Yang W, Liu L. Determination of Dielectric Properties of Cells using AC Electrokinetic-based Microfluidic Platform: A Review of Recent Advances. MICROMACHINES 2020; 11:E513. [PMID: 32438680 PMCID: PMC7281274 DOI: 10.3390/mi11050513] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/16/2020] [Accepted: 05/18/2020] [Indexed: 12/18/2022]
Abstract
Cell dielectric properties, a type of intrinsic property of cells, can be used as electrophysiological biomarkers that offer a label-free way to characterize cell phenotypes and states, purify clinical samples, and identify target cancer cells. Here, we present a review of the determination of cell dielectric properties using alternating current (AC) electrokinetic-based microfluidic mechanisms, including electro-rotation (ROT) and dielectrophoresis (DEP). The review covers theoretically how ROT and DEP work to extract cell dielectric properties. We also dive into the details of differently structured ROT chips, followed by a discussion on the determination of cell dielectric properties and the use of these properties in bio-related applications. Additionally, the review offers a look at the future challenges facing the AC electrokinetic-based microfluidic platform in terms of acquiring cell dielectric parameters. Our conclusion is that this platform will bring biomedical and bioengineering sciences to the next level and ultimately achieve the shift from lab-oriented research to real-world applications.
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Affiliation(s)
- Wenfeng Liang
- School of Mechanical Engineering, Shenyang Jianzhu University, Shenyang 110168, China; (X.Y.); (J.W.)
| | - Xieliu Yang
- School of Mechanical Engineering, Shenyang Jianzhu University, Shenyang 110168, China; (X.Y.); (J.W.)
| | - Junhai Wang
- School of Mechanical Engineering, Shenyang Jianzhu University, Shenyang 110168, China; (X.Y.); (J.W.)
| | - Yuechao Wang
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China;
| | - Wenguang Yang
- School of Electromechanical and Automotive Engineering, Yantai University, Yantai 264005, China;
| | - Lianqing Liu
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China;
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15
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García Núñez C, Braña AF, López N, Pau JL, García BJ. Single GaAs nanowire based photodetector fabricated by dielectrophoresis. NANOTECHNOLOGY 2020; 31:225604. [PMID: 32187022 DOI: 10.1088/1361-6528/ab76ee] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Mechanical manipulation of nanowires (NWs) for their integration in electronics is still problematic because of their reduced dimensions, risking to produce mechanical damage to the NW structure and electronic properties during the assembly process. In this regard, contactless NW manipulation based methods using non-uniform electric fields, like dielectrophoresis (DEP) are usually much softer than mechanical methods, offering a less destructive alternative for integrating nanostructures in electronic devices. Here, we report a feasible and reproducible dielectrophoretic method to assemble single GaAs NWs (with radius 35-50 nm, and lengths 3-5 μm) on conductive electrodes layout with assembly yields above 90% per site, and alignment yields of 95%. The electrical characteristics of the dielectrophoretic contact formed between a GaAs NW and conductive electrodes have been measured, observing Schottky barrier like contacts. Our results also show the fast fabrication of diodes with rectifying characteristics due to the formation of a low-resistance contact between the Ga catalytic droplet at the tip of the NW when using Al doped ZnO as electrode. The current-voltage characteristics of a single Ga-terminated GaAs NW measured in dark and under illumination exhibit a strong sensitivity to visible light under forward bias conditions (around two orders of magnitude), mainly produced by a change on the series resistance of the device.
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Affiliation(s)
- Carlos García Núñez
- Electronics and Semiconductors Group (ELySE), Applied Physics Department, Universidad Autónoma de Madrid (UAM), 28049 Madrid, Spain. Scottish Universities Physics Alliance (SUPA), Institute of Thin Films, Sensors & Imaging (TFSI), University of the West of Scotland (UWS), Paisley PA1 2BE, United Kingdom
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Mohammadi S, Nadaraja AV, Luckasavitch K, Jain MC, June Roberts D, Zarifi MH. A Label-Free, Non-Intrusive, and Rapid Monitoring of Bacterial Growth on Solid Medium Using Microwave Biosensor. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2020; 14:2-11. [PMID: 31715571 DOI: 10.1109/tbcas.2019.2952841] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Microwave resonator sensors are attractive for their contactless and label-free capability of monitoring bacterial growth in liquid media. This paper outlines a new label-free microwave biosensor based on a pair of planar split ring resonators for non-invasive monitoring of bacterial growth on a solid agar media. The sensor is comprised of two split ring resonators with slightly different resonant frequencies for differential operation. The transmission coefficient (S21) of the sensor is considered as the sensor's response with a designed and measured quality factor above 200 to ensure a high-resolution operation of the biosensor. Two resonant frequencies of 1.95 and 2.11 GHz represent the sensing signal and the reference signal, respectively. The developed sensor demonstrates high performance in monitoring the growth dynamics of Escherichia coli (E. coli) on Luria-Bertani (LB) agar with 4 mm thickness. The sensor's resonant amplitude response demonstrated 0.5 dB variation corresponding to the bacterial growth over 48 hours when bacteria were spread on LB agar starting with initial OD600 = 1.5. Moreover, 0.6 dB change in the sensor's response was observed over 96 hours of bacterial growth starting with an initial OD600 = 1.17 spotted on LB agar. The measured results fit well to the curves created using Richards' bacterial growth model, showing the strength of the sensor as a potential candidate for use in predictive food microbiology systems.
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Chen Q, Cao Z, Yuan YJ. Study on non-bioparticles and Staphylococcus aureus by dielectrophoresis. RSC Adv 2020; 10:2598-2614. [PMID: 35496126 PMCID: PMC9048846 DOI: 10.1039/c9ra05886a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 12/28/2019] [Indexed: 01/09/2023] Open
Abstract
This article demonstrated a chip device with alternating current (AC) dielectrophoresis (DEP) for separation of non-biological micro-particle and bacteria mixtures. The DEP separation was achieved by a pair of metal electrodes with the shape of radal-interdigital to generate a localized non-uniform AC electric field. The electric field and DEP force were firstly investigated by finite element methods (FEM). The mixed microparticles such as different scaled polystyrene (PS) beads, PS beads with inorganic micro-particles (e.g., ZnO and silica beads) and non-bioparticles with bacterial Staphylococcus aureus (S. aureus) were successfully separated at DEP-on-a-chip by an AC electric field of 20 kHz, 10 kHz and 1 MHz, respectively. The results indicated that DEP trapping can be considered as a potential candidate method for investigating the separation of biological mixtures, and may well prove to have a great impact on in situ monitoring of environmental and/or biological samples by DEP-on-a-chip. This article demonstrated a chip device with alternating current (AC) dielectrophoresis (DEP) for separation of non-biological micro-particle and bacteria mixtures.![]()
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Affiliation(s)
- Qiaoying Chen
- Laboratory of Biosensing and MicroMechatronics
- School of Materials Science and Engineering
- Southwest Jiaotong University
- Chengdu
- China
| | - Zhongqing Cao
- School of Mechanical Engineering
- Southwest Jiaotong University
- Chengdu
- China
| | - Yong J. Yuan
- Laboratory of Biosensing and MicroMechatronics
- School of Materials Science and Engineering
- Southwest Jiaotong University
- Chengdu
- China
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Miller C, Stiglich M, Livingstone M, Gilmore J. Impedance-Based Biosensing of Pseudomonas putida via Solution Blow Spun PLA: MWCNT Composite Nanofibers. MICROMACHINES 2019; 10:mi10120876. [PMID: 31847091 PMCID: PMC6952954 DOI: 10.3390/mi10120876] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 12/06/2019] [Accepted: 12/10/2019] [Indexed: 11/16/2022]
Abstract
Quantifiable sensing of common microbes in chronic wounds has the potential to enable an objective assessment of wound healing for diagnostic applications. Sensing platforms should be robust, simple, and flexible to provide clinicians with a point-of-care tool. In this work, solution blow spun poly (lactic acid)/multiwalled carbon nanotube nanofiber composites are used to detect the presence and concentration of Pseudomonas putida in vitro using changes in impedance. Impedance microbiology (IM) is a well-documented diagnostic technique used in many applications, including cancer detection, tuberculosis screening and pregnancy tests. Twenty-four hour real-time measurements of the equivalent circuit of three culture media were taken with an inductance, capacitance, and resistance (LCR) meter. Variations in impedance were calculated to correspond to the growth of P. putida. Additionally, instantaneous measurements of bacterial cultures were taken over a one-minute time point to display the fast sensing of bacterial load via IM. This proof-of-concept shows that conductive solution blow spun fiber mats is a valid fabrication technique to develop in situ wound dressing impedance sensors. Study results indicate successful measurement and quantification of bacterial growth in this proof-of-concept study.
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Checa M, Millan-Solsona R, Blanco N, Torrents E, Fabregas R, Gomila G. Mapping the dielectric constant of a single bacterial cell at the nanoscale with scanning dielectric force volume microscopy. NANOSCALE 2019; 11:20809-20819. [PMID: 31657419 DOI: 10.1039/c9nr07659j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Mapping the dielectric constant at the nanoscale of samples showing a complex topography, such as non-planar nanocomposite materials or single cells, poses formidable challenges to existing nanoscale dielectric microscopy techniques. Here we overcome these limitations by introducing Scanning Dielectric Force Volume Microscopy. This scanning probe microscopy technique is based on the acquisition of electrostatic force approach curves at every point of a sample and its post-processing and quantification by using a computational model that incorporates the actual measured sample topography. The technique provides quantitative nanoscale images of the local dielectric constant of the sample with unparalleled accuracy, spatial resolution and statistical significance, irrespectively of the complexity of its topography. We illustrate the potential of the technique by presenting a nanoscale dielectric constant map of a single bacterial cell, including its small-scale appendages. The bacterial cell shows three characteristic equivalent dielectric constant values, namely, εr,bac1 = 2.6 ± 0.2, εr,bac2 = 3.6 ± 0.4 and εr,bac3 = 4.9 ± 0.5, which enable identifying different dielectric properties of the cell wall and of the cytoplasmatic region, as well as, the existence of variations in the dielectric constant along the bacterial cell wall itself. Scanning Dielectric Force Volume Microscopy is expected to have an important impact in Materials and Life Sciences where the mapping of the dielectric properties of samples showing complex nanoscale topographies is often needed.
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Affiliation(s)
- Martí Checa
- Nanoscale Bioelectrical Characterization, Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology, c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain. and Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, c/Martí i Franquès 1, 08028, Barcelona, Spain
| | - Ruben Millan-Solsona
- Nanoscale Bioelectrical Characterization, Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology, c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain. and Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, c/Martí i Franquès 1, 08028, Barcelona, Spain
| | - Nuria Blanco
- Bacterial Infections: Antimicrobial Therapies, Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology, c/Baldiri i Reixac 11-15, 08028, Barcelona
| | - Eduard Torrents
- Bacterial Infections: Antimicrobial Therapies, Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology, c/Baldiri i Reixac 11-15, 08028, Barcelona
| | - Rene Fabregas
- Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, c/Martí i Franquès 1, 08028, Barcelona, Spain
| | - Gabriel Gomila
- Nanoscale Bioelectrical Characterization, Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology, c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain. and Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, c/Martí i Franquès 1, 08028, Barcelona, Spain
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20
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Zhao W, Cui W, Xu S, Cheong LZ, Wang D, Shen C. Direct study of the electrical properties of PC12 cells and hippocampal neurons by EFM and KPFM. NANOSCALE ADVANCES 2019; 1:537-545. [PMID: 36132273 PMCID: PMC9473159 DOI: 10.1039/c8na00202a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 11/19/2018] [Indexed: 05/30/2023]
Abstract
Electrical related properties play important roles in biological structures and functions. Herein, the capacitance gradient and local contact potential difference (CPD) of cell bodies and processes of PC12 cells (representative cells of the sympathetic nervous system), hippocampal neurons (representative cells of the central nervous system) and spines were investigated by Electrostatic Force Microscopy (EFM) and Kelvin Probe Force Microscopy (KPFM) at high lateral spatial resolution directly. The results demonstrate that the capacitance gradients of cell bodies, processes and spines of PC12 cells and hippocampal neurons are very close (in the range of 19-23 zF nm-1) and fit well with the theoretical calculation results (21.7 zF nm-1). This indicates that the differences of nerve signal activities and functions of the sympathetic and central nervous systems are not related to the electric polarization properties. The CPD of cell bodies and processes of PC12 cells is smaller than that of hippocampal neurons. The CPD of spines is much more negative than that of the cell bodies and processes. These results reveal that the surface potential is closely related to the neural signal transduction functions, and spines play vital roles in neural signal transmission. This work indicates the similarity (capacitance gradient) and differences (surface potential) of the electrical properties between the sympathetic and central nervous systems for the first time. The methods and results of this work are useful in the further study of the electrical properties in cellular activities and physiological processes.
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Affiliation(s)
- Weidong Zhao
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences 1219 Zhongguan Road Ningbo Zhejiang China
| | - Wei Cui
- Ningbo Key Laboratory of Behavioral Neuroscience, Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University Ningbo Zhejiang China
| | - Shujun Xu
- Ningbo Key Laboratory of Behavioral Neuroscience, Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University Ningbo Zhejiang China
| | - Ling-Zhi Cheong
- School of Marine Science, Ningbo University Ningbo 315211 China
| | - Deyu Wang
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences 1219 Zhongguan Road Ningbo Zhejiang China
| | - Cai Shen
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences 1219 Zhongguan Road Ningbo Zhejiang China
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Bacteria Detection and Differentiation Using Impedance Flow Cytometry. SENSORS 2018; 18:s18103496. [PMID: 30336557 PMCID: PMC6210208 DOI: 10.3390/s18103496] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/11/2018] [Accepted: 10/15/2018] [Indexed: 12/01/2022]
Abstract
Monitoring of bacteria concentrations is of great importance in drinking water management. Continuous real-time monitoring enables better microbiological control of the water and helps prevent contaminated water from reaching the households. We have developed a microfluidic sensor with the potential to accurately assess bacteria levels in drinking water in real-time. Multi frequency electrical impedance spectroscopy is used to monitor a liquid sample, while it is continuously passed through the sensor. We investigate three aspects of this sensor: First we show that the sensor is able to differentiate Escherichia coli (Gram-negative) bacteria from solid particles (polystyrene beads) based on an electrical response in the high frequency phase and individually enumerate the two samples. Next, we demonstrate the sensor’s ability to measure the bacteria concentration by comparing the results to those obtained by the traditional CFU counting method. Last, we show the sensor’s potential to distinguish between different bacteria types by detecting different signatures for S. aureus and E. coli mixed in the same sample. Our investigations show that the sensor has the potential to be extremely effective at detecting sudden bacterial contaminations found in drinking water, and eventually also identify them.
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Goel M, Verma A, Gupta S. Electric-field driven assembly of live bacterial cell microarrays for rapid phenotypic assessment and cell viability testing. Biosens Bioelectron 2018; 111:159-165. [DOI: 10.1016/j.bios.2018.04.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/29/2018] [Accepted: 04/03/2018] [Indexed: 12/15/2022]
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A Novel Pathogen Capturing Device for Removal and Detection. Sci Rep 2017; 7:5552. [PMID: 28717239 PMCID: PMC5514083 DOI: 10.1038/s41598-017-05854-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/23/2017] [Indexed: 01/03/2023] Open
Abstract
A simple technique that employs an antibody coated polydimethylsiloxane tube is used for effective capturing of bloodborne and foodborne pathogens. By recirculating the entire sample through the antibody coated tube, accumulation of target pathogens is achieved, thereby delivering a higher concentration of pathogens in a small volume. The described method can provide an effective and economical solution to microbiology techniques that rely on enrichment, thereby expediting diagnostics. Using this method 80.3 ± 5.6% of Staphylococcus aureus with a starting concentration of ~107 CFU/mL and 95.4 ± 1.0% of Methicillin-resistant Staphylococcus aureus with starting concentration of ~104 CFU/mL were removed from 5 mL blood in a few hours. This concept was extended to live rats with an induced bloodstream S. aureus infection. A reduction of two orders of magnitude in the bacterial load of the rats was observed within a few hours. The same technique was used to capture a food pathogen, Salmonella typhimurium, with starting concentrations as low as ~100 CFU, from 100 or 250 mL of culture broth within similar timeframes as above. The feasibility for food pathogen testing applications was additionally confirmed by capturing and detecting S. typhimurium in ground chicken and ground beef.
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Paulitsch-Fuchs AH, Zsohár A, Wexler AD, Zauner A, Kittinger C, de Valença J, Fuchs EC. Behavioral study of selected microorganisms in an aqueous electrohydrodynamic liquid bridge. Biochem Biophys Rep 2017; 10:287-296. [PMID: 29114576 PMCID: PMC5627143 DOI: 10.1016/j.bbrep.2017.04.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 03/09/2017] [Accepted: 04/22/2017] [Indexed: 11/18/2022] Open
Abstract
An aqueous electrohydrodynamic (EHD) floating liquid bridge is a unique environment for studying the influence of protonic currents (mA cm-2) in strong DC electric fields (kV cm-1) on the behavior of microorganisms. It forms in between two beakers filled with water when high-voltage is applied to these beakers. We recently discovered that exposure to this bridge has a stimulating effect on Escherichia coli.. In this work we show that the survival is due to a natural Faraday cage effect of the cell wall of these microorganisms using a simple 2D model. We further confirm this hypothesis by measuring and simulating the behavior of Bacillus subtilis subtilis, Neochloris oleoabundans, Saccharomyces cerevisiae and THP-1 monocytes. Their behavior matches the predictions of the model: cells without a natural Faraday cage like algae and monocytes are mostly killed and weakened, whereas yeast and Bacillus subtilis subtilis survive. The effect of the natural Faraday cage is twofold: First, it diverts the current from passing through the cell (and thereby killing it); secondly, because it is protonic it maintains the osmotic pressure in the cell wall, thereby mitigating cytolysis which would normally occur due to the low osmotic pressure of the surrounding medium. The method presented provides the basis for selective disinfection of solutions containing different microorganisms.
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Affiliation(s)
- Astrid H. Paulitsch-Fuchs
- Wetsus, European Centre of Excellence for Sustainable Water Technology,
Leeuwarden, The Netherlands
- Institute of Hygiene, Microbiology and Environmental Medicine, Medical
University of Graz, Graz, Austria
| | - Andrea Zsohár
- Wetsus, European Centre of Excellence for Sustainable Water Technology,
Leeuwarden, The Netherlands
| | - Adam D. Wexler
- Wetsus, European Centre of Excellence for Sustainable Water Technology,
Leeuwarden, The Netherlands
| | - Andrea Zauner
- Institute of Hygiene, Microbiology and Environmental Medicine, Medical
University of Graz, Graz, Austria
| | - Clemens Kittinger
- Institute of Hygiene, Microbiology and Environmental Medicine, Medical
University of Graz, Graz, Austria
| | - Joeri de Valença
- Wetsus, European Centre of Excellence for Sustainable Water Technology,
Leeuwarden, The Netherlands
| | - Elmar C. Fuchs
- Wetsus, European Centre of Excellence for Sustainable Water Technology,
Leeuwarden, The Netherlands
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Weng PY, Chen IA, Yeh CK, Chen PY, Juang JY. Size-dependent dielectrophoretic crossover frequency of spherical particles. BIOMICROFLUIDICS 2016; 10:011909. [PMID: 26909121 PMCID: PMC4752537 DOI: 10.1063/1.4941853] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Accepted: 02/01/2016] [Indexed: 05/25/2023]
Abstract
Dielectrophoresis (DEP) has been extensively used in lab-on-a-chip systems for trapping, separating, and manipulating of micro particles suspended in a liquid medium. The most widely used analytic model, the dipole model, provides an accurate prediction on the crossover frequency of submicron particles, but cannot explain the significant drop in crossover frequency of larger particles. Here, we present numerical simulations using the Maxwell stress tensor (MST) and finite element method to study the size effect of the DEP crossover frequency of spherical polystyrene particles suspended in de-ionized water. Our results show that the surface conductance due to the electrical double layer plays a key role, and the size dependency of crossover frequency obtained by the MST method agrees reasonably well with published experimental data. The exponents of the power law are approximately -1.0 and -4.3 for smaller (diameter < 4.6 μm) and larger particles (diameter > 4.6 μm), respectively. The free surface charge distribution reveals that the charge begins accumulating on the particle equator for particle diameters larger than a critical diameter of 4.6 μm, a result not captured by the dipolar approximation. This method may be extended to analyze bioparticles with complex shapes and composition, and provides new insights into the interpretation of dielectrophoresis applications using lab-on-a-chip systems.
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Affiliation(s)
- Ping-You Weng
- Department of Mechanical Engineering, National Taiwan University , Taipei 10617, Taiwan
| | - I-An Chen
- Department of Mechanical Engineering, National Taiwan University , Taipei 10617, Taiwan
| | - Che-Kai Yeh
- Department of Mechanical Engineering, National Taiwan University , Taipei 10617, Taiwan
| | - Pin-Yi Chen
- Department of Mechanical Engineering, National Taiwan University , Taipei 10617, Taiwan
| | - Jia-Yang Juang
- Department of Mechanical Engineering, National Taiwan University , Taipei 10617, Taiwan
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Couniot N, Francis LA, Flandre D. Resonant dielectrophoresis and electrohydrodynamics for high-sensitivity impedance detection of whole-cell bacteria. LAB ON A CHIP 2015; 15:3183-3191. [PMID: 26120099 DOI: 10.1039/c5lc00090d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present the co-integration of CMOS-compatible Al/Al2O3 interdigitated microelectrodes (IDEs) with an electrokinetic-driven macroelectrode for sensitive detection of whole-cell bacteria in a microfluidic channel. Two frequency ranges applied to the macroelectrode were identified to notably increase the bacterial coverage of the impedimetric sensor per unit time. Around 10 kHz, the bacterial cells were directed towards the IDE center thanks to AC electroosmosis (AC-EO) and the sensor capacitance linearly increased, achieving a limit of detection (LoD) of 3.5 × 10(5) CFU mL(-1) after an incubation time of 20 min with Staphylococcus epidermidis. At 63 MHz precisely, a resonance effect due to the device was found to dramatically increase the trapping of S. epidermidis on the sensor periphery, due to the combined actions of short-range contactless dielectrophoresis (cDEP) and long-range Joule heating electrothermal (J-ET) flow. Thanks to a flow-based method, the bacterial cells were redirected towards the sensor center and an LoD of 10(5) CFU mL(-1) was achieved within 20 min of incubation, which is almost two orders of magnitude better than the impedimetric sensor alone. Analytical models and 2D simulations using the Maxwell stress tensor (MST) provide a comprehensive analysis of the experimental results, especially about the spectral balance between cDEP, AC-EO and J-ET accounting for the 33-nm thick insulating layer atop the electrodes. Electrode CMOS compatibility confers portability, miniaturization and affordability capabilities for building point-of-care (PoC) diagnostic tests in a lab-on-a-chip (LoC).
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Affiliation(s)
- Numa Couniot
- ICTEAM Institute, Université Catholique de Louvain (UCL), Place du Levant 3-L5.03.02, 1348 Louvain-La-Neuve, Belgium.
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Couniot N, Vanzieleghem T, Rasson J, Van Overstraeten-Schlögel N, Poncelet O, Mahillon J, Francis L, Flandre D. Lytic enzymes as selectivity means for label-free, microfluidic and impedimetric detection of whole-cell bacteria using ALD-Al2O3 passivated microelectrodes. Biosens Bioelectron 2015; 67:154-61. [DOI: 10.1016/j.bios.2014.07.084] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/11/2014] [Accepted: 07/31/2014] [Indexed: 10/24/2022]
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28
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Kim D, Shim J, Chuang HS, Kim KC. Numerical simulation on the opto-electro-kinetic patterning for rapid concentration of particles in a microchannel. BIOMICROFLUIDICS 2015; 9:034102. [PMID: 26015839 PMCID: PMC4433480 DOI: 10.1063/1.4921232] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 05/06/2015] [Indexed: 05/04/2023]
Abstract
This paper presents a mathematical model for laser-induced rapid electro-kinetic patterning (REP) to elucidate the mechanism for concentrating particles in a microchannel non-destructively and non-invasively. COMSOL(®)(v4.2a) multiphysics software was used to examine the effect of a variety of parameters on the focusing performance of the REP. A mathematical model of the REP was developed based on the AC electrothermal flow (ACET) equations, the dielectrophoresis (DEP) equation, the energy balance equation, the Navier-Stokes equation, and the concentration-distribution equation. The medium was assumed to be a diluted solute, and different electric potentials and laser illumination were applied to the desired place. Gold (Au) electrodes were used at the top and bottom of a microchannel. For model validation, the simulation results were compared with the experimental data. The results revealed the formation of a toroidal microvortex via the ACET effect, which was generated due to laser illumination and joule-heating in the area of interest. In addition, under some conditions, such as the frequency of AC, the DEP velocity, and the particle size, the ACET force enhances and compresses resulting in the concentration of particles. The conditions of the DEP velocity and the ACET velocity are presented in detail with a comparison of the experimental results.
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Affiliation(s)
- Dong Kim
- School of Mechanical Engineering, Pusan National University , Busan 609-735, South Korea
| | - Jaesool Shim
- School of Mechanical Engineering, Yeungnam University , Gyeongsan 712-749, South Korea
| | - Han-Sheng Chuang
- Department of Biomedical Engineering, National Cheng Kung University , Tainan, Taiwan
| | - Kyung Chun Kim
- School of Mechanical Engineering, Pusan National University , Busan 609-735, South Korea
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Nakidde D, Zellner P, Alemi MM, Shake T, Hosseini Y, Riquelme MV, Pruden A, Agah M. Three dimensional passivated-electrode insulator-based dielectrophoresis. BIOMICROFLUIDICS 2015; 9:014125. [PMID: 25784964 PMCID: PMC4344466 DOI: 10.1063/1.4913497] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/12/2015] [Indexed: 05/14/2023]
Abstract
In this study, a 3D passivated-electrode, insulator-based dielectrophoresis microchip (3D πDEP) is presented. This technology combines the benefits of electrode-based DEP, insulator-based DEP, and three dimensional insulating features with the goal of improving trapping efficiency of biological species at low applied signals and fostering wide frequency range operation of the microfluidic device. The 3D πDEP chips were fabricated by making 3D structures in silicon using reactive ion etching. The reusable electrodes are deposited on second glass substrate and then aligned to the microfluidic channel to capacitively couple the electric signal through a 100 μm glass slide. The 3D insulating structures generate high electric field gradients, which ultimately increases the DEP force. To demonstrate the capabilities of 3D πDEP, Staphylococcus aureus was trapped from water samples under varied electrical environments. Trapping efficiencies of 100% were obtained at flow rates as high as 350 μl/h and 70% at flow rates as high as 750 μl/h. Additionally, for live bacteria samples, 100% trapping was demonstrated over a wide frequency range from 50 to 400 kHz with an amplitude applied signal of 200 Vpp. 20% trapping of bacteria was observed at applied voltages as low as 50 Vpp. We demonstrate selective trapping of live and dead bacteria at frequencies ranging from 30 to 60 kHz at 400 Vpp with over 90% of the live bacteria trapped while most of the dead bacteria escape.
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Affiliation(s)
- Diana Nakidde
- VT MEMS - Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24060 , USA
| | - Phillip Zellner
- VT MEMS - Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24060 , USA
| | | | - Tyler Shake
- VT MEMS - Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24060 , USA
| | - Yahya Hosseini
- VT MEMS - Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24060 , USA
| | - Maria V Riquelme
- Pruden Lab - Department of Civil and Environmental Engineering , Virginia Tech, Blacksburg, Virginia 24060, USA
| | - Amy Pruden
- Pruden Lab - Department of Civil and Environmental Engineering , Virginia Tech, Blacksburg, Virginia 24060, USA
| | - Masoud Agah
- VT MEMS - Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24060 , USA
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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
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31
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Esteban-Ferrer D, Edwards MA, Fumagalli L, Juárez A, Gomila G. Electric polarization properties of single bacteria measured with electrostatic force microscopy. ACS NANO 2014; 8:9843-9. [PMID: 25184827 DOI: 10.1021/nn5041476] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We quantified the electrical polarization properties of single bacterial cells using electrostatic force microscopy. We found that the effective dielectric constant, ε(r,eff), for the four bacterial types investigated (Salmonella typhimurium, Escherchia coli, Lactobacilus sakei, and Listeria innocua) is around 3-5 under dry air conditions. Under ambient humidity, it increases to ε(r,eff) ∼ 6-7 for the Gram-negative bacterial types (S. typhimurium and E. coli) and to ε(r,eff) ∼ 15-20 for the Gram-positive ones (L. sakei and L. innocua). We show that the measured effective dielectric constants can be consistently interpreted in terms of the electric polarization properties of the biochemical components of the bacterial cell compartments and of their hydration state. These results demonstrate the potential of electrical studies of single bacterial cells.
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Affiliation(s)
- Daniel Esteban-Ferrer
- Institut de Bioenginyeria de Catalunya (IBEC) , C/Baldiri i Reixac 11-15, 08028 Barcelona, Spain
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32
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Nili H, Green NG. Higher-order dielectrophoresis of nonspherical particles. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:063302. [PMID: 25019907 DOI: 10.1103/physreve.89.063302] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Indexed: 06/03/2023]
Abstract
Higher-order terms of dielectrophoretic (DEP) force are commonly ignored by invoking the simplifying dipole approximation. Concurrently, the trend towards micro- and nano-electrode structures in DEP design is bringing about an increasing number of instances where the approximation is expected to lose reliability. The case is severe for nonspherical particles (the shape of many biological particles) due to the shape-dependent nature of dielectric polarization. However, there is a lack of analytical means to determine multipole moments of nonspherical particles, numerical calculations of the same are regarded as unreliable, and there is a prevalence for higher-order force considerations to be ignored. As a result, the dipole approximation is used and/or nonspherical particles are approximated as spheres. This work proves the inefficacy of current qualitative criteria for the reliability of the dipole approximation and presents a quantitative substitute, with verified accuracy, that enables precise determination of the extent to which the dipole approximation would be reliable, and if found unreliable, corrects the approximation by adding second- and third-order terms of the DEP force. The effects of field nonuniformity, electrode design, and particle shape and aspect ratio on the significance of higher-order DEP forces is quantitatively analyzed. The results show that higher-order DEP forces are indeed of substantially increased significance for nonspherical particles; in the cases examined in this work, multipolar terms are seen to constitute more than 40% of the total force on ellipsoidal and cylindrical particles. It is further shown that approximating nonspherical particles as spheres of similar dimensions is subject to substantial error. Last, the substantial importance of the electrode design in influencing higher-order forces is shown.
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Affiliation(s)
- Hossein Nili
- Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK
| | - Nicolas G Green
- Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK
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33
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Kim I, An T, Choi W, Kim CS, Cha HJ, Lim G. Site-specific immobilization of microbes using carbon nanotubes and dielectrophoretic force for microfluidic applications. RSC Adv 2014. [DOI: 10.1039/c3ra45155k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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34
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Embedded passivated-electrode insulator-based dielectrophoresis (EπDEP). Anal Bioanal Chem 2013; 405:9825-33. [DOI: 10.1007/s00216-013-7435-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 10/09/2013] [Accepted: 10/11/2013] [Indexed: 12/21/2022]
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35
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Huang C, Santana SM, Liu H, Bander NH, Hawkins BG, Kirby BJ. Characterization of a hybrid dielectrophoresis and immunocapture microfluidic system for cancer cell capture. Electrophoresis 2013; 34:2970-9. [PMID: 23925921 DOI: 10.1002/elps.201300242] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 07/21/2013] [Accepted: 07/24/2013] [Indexed: 01/18/2023]
Abstract
The capture of circulating tumor cells (CTCs) from cancer patient blood enables early clinical assessment as well as genetic and pharmacological evaluation of cancer and metastasis. Although there have been many microfluidic immunocapture and electrokinetic techniques developed for isolating rare cancer cells, these techniques are often limited by a capture performance tradeoff between high efficiency and high purity. We present the characterization of shear-dependent cancer cell capture in a novel hybrid DEP-immunocapture system consisting of interdigitated electrodes fabricated in a Hele-Shaw flow cell that was functionalized with a monoclonal antibody, J591, which is highly specific to prostate-specific membrane antigen expressing prostate cancer cells. We measured the positive and negative DEP response of a prostate cancer cell line, LNCaP, as a function of applied electric field frequency, and showed that DEP can control capture performance by promoting or preventing cell interactions with immunocapture surfaces, depending on the sign and magnitude of the applied DEP force, as well as on the local shear stress experienced by cells flowing in the device. This work demonstrates that DEP and immunocapture techniques can work synergistically to improve cell capture performance, and it will aid in the design of future hybrid DEP-immunocapture systems for high-efficiency CTC capture with enhanced purity.
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Affiliation(s)
- Chao Huang
- Department of Biomedical Engineering, Cornell University, Ithaca, NY, USA
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36
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Madiyar FR, Syed LU, Arumugam P, Li J. Electrical Capture and Detection of Microbes Using Dielectrophoresis at Nanoelectrode Arrays. ACTA ACUST UNITED AC 2013. [DOI: 10.1021/bk-2013-1143.ch006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Affiliation(s)
- Foram Ranjeet Madiyar
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506-0401
- Advanced Diamond Technologies Inc., 48 East Belmont Drive, Romeoville, Illinois 60446
| | - Lateef Uddin Syed
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506-0401
- Advanced Diamond Technologies Inc., 48 East Belmont Drive, Romeoville, Illinois 60446
| | - Prabhu Arumugam
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506-0401
- Advanced Diamond Technologies Inc., 48 East Belmont Drive, Romeoville, Illinois 60446
| | - Jun Li
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506-0401
- Advanced Diamond Technologies Inc., 48 East Belmont Drive, Romeoville, Illinois 60446
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37
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Abdallat RG, Ahmad Tajuddin AS, Gould DH, Hughes MP, Fatoyinbo HO, Labeed FH. Process development for cell aggregate arrays encapsulated in a synthetic hydrogel using negative dielectrophoresis. Electrophoresis 2013; 34:1059-67. [PMID: 23436271 DOI: 10.1002/elps.201200459] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Revised: 12/27/2012] [Accepted: 01/02/2013] [Indexed: 12/19/2022]
Abstract
Spatial patterning of cells is of great importance in tissue engineering and biotechnology, enabling, for example the creation of bottom-up histoarchitectures of heterogeneous cells, or cell aggregates for in vitro high-throughput toxicological and therapeutic studies within 3D microenvironments. In this paper, a single-step process for creating peelable and resilient hydrogels, encapsulating arrays of biological cell aggregates formed by negative DEP has been devised. The dielectrophoretic trapping within low-energy regions of the DEP-dot array reduces cell exposure to high field stresses while creating distinguishable, evenly spaced arrays of aggregates. In addition to using an optimal combination of PEG diacrylate pre-polymer solution concentration and a novel UV exposure mechanism, total processing time was reduced. With a continuous phase medium of PEG diacrylate at 15% v/v concentration, effective dielectrophoretic cell patterned arrays and photo-polymerisation of the mixture was achieved within a 4 min period. This unique single-step process was achieved using a 30 s UV exposure time frame within a dedicated, wide exposure area DEP light box system. To demonstrate the developed process, aggregates of yeast, human leukemic (K562) and HeLa cells were immobilised in an array format within the hydrogel. Relative cell viability for both cells within the hydrogels, after maintaining them in appropriate iso-osmotic media, over a week period was greater than 90%.
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Affiliation(s)
- Rula G Abdallat
- Faculty of Engineering and Physical Sciences, Centre for Biomedical Engineering, University of Surrey, Guildford, Surrey, United Kingdom
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38
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Cetin B, Li D. Dielectrophoresis in microfluidics technology. Electrophoresis 2011; 32:2410-27. [PMID: 21922491 DOI: 10.1002/elps.201100167] [Citation(s) in RCA: 194] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 06/09/2011] [Accepted: 06/09/2011] [Indexed: 01/12/2023]
Abstract
Dielectrophoresis (DEP) is the movement of a particle in a non-uniform electric field due to the interaction of the particle's dipole and spatial gradient of the electric field. DEP is a subtle solution to manipulate particles and cells at microscale due to its favorable scaling for the reduced size of the system. DEP has been utilized for many applications in microfluidic systems. In this review, a detailed analysis of the modeling of DEP-based manipulation of the particles is provided, and the recent applications regarding the particle manipulation in microfluidic systems (mainly the published works between 2007 and 2010) are presented.
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Affiliation(s)
- Barbaros Cetin
- Mechanical Engineering, Middle East Technical University, Northern Cyprus Campus, Güzelyurt, Turkey.
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39
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Hawkins BG, Huang C, Arasanipalai S, Kirby BJ. Automated Dielectrophoretic Characterization of Mycobacterium smegmatis. Anal Chem 2011; 83:3507-15. [DOI: 10.1021/ac2002017] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Benjamin G. Hawkins
- Department of Biomedical Engineering, and ‡Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York, United States
| | - Chao Huang
- Department of Biomedical Engineering, and ‡Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York, United States
| | - Srinitya Arasanipalai
- Department of Biomedical Engineering, and ‡Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York, United States
| | - Brian J. Kirby
- Department of Biomedical Engineering, and ‡Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York, United States
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40
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Specific electromagnetic effects of microwave radiation on Escherichia coli. Appl Environ Microbiol 2011; 77:3017-22. [PMID: 21378041 DOI: 10.1128/aem.01899-10] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The present study investigated the effects of microwave (MW) radiation applied under a sublethal temperature on Escherichia coli. The experiments were conducted at a frequency of 18 GHz and at a temperature below 40°C to avoid the thermal degradation of bacterial cells during exposure. The absorbed power was calculated to be 1,500 kW/m(3), and the electric field was determined to be 300 V/m. Both values were theoretically confirmed using CST Microwave Studio 3D Electromagnetic Simulation Software. As a negative control, E. coli cells were also thermally heated to temperatures up to 40°C using Peltier plate heating. Scanning electron microscopy (SEM) analysis performed immediately after MW exposure revealed that the E. coli cells exhibited a cell morphology significantly different from that of the negative controls. This MW effect, however, appeared to be temporary, as following a further 10-min elapsed period, the cell morphology appeared to revert to a state that was identical to that of the untreated controls. Confocal laser scanning microscopy (CLSM) revealed that fluorescein isothiocyanate (FITC)-conjugated dextran (150 kDa) was taken up by the MW-treated cells, suggesting that pores had formed within the cell membrane. Cell viability experiments revealed that the MW treatment was not bactericidal, since 88% of the cells were recovered after radiation. It is proposed that one of the effects of exposing E. coli cells to MW radiation under sublethal temperature conditions is that the cell surface undergoes a modification that is electrokinetic in nature, resulting in a reversible MW-induced poration of the cell membrane.
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41
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Hawkins BG, Kirby BJ. Electrothermal flow effects in insulating (electrodeless) dielectrophoresis systems. Electrophoresis 2011; 31:3622-33. [PMID: 21077234 DOI: 10.1002/elps.201000429] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We simulate electrothermally induced flow in polymeric, insulator-based dielectrophoresis (iDEP) systems with DC-offset, AC electric fields at finite thermal Péclet number, and we identify key regimes where electrothermal (ET) effects enhance particle deflection and trapping. We study a single, two-dimensional constriction in channel depth with parametric variations in electric field, channel geometry, fluid conductivity, particle electrophoretic (EP) mobility, and channel electroosmotic (EO) mobility. We report the effects of increasing particle EP mobility, channel EO mobility, and AC and DC field magnitudes on the mean constriction temperature and particle behavior. Specifically, we quantify particle deflection and trapping, referring to the deviation of particles from their pathlines due to dielectrophoresis as they pass a constriction and the stagnation of particles due to negative dielectrophoresis near a constriction, respectively. This work includes the coupling between fluid, heat, and electromagnetic phenomena via temperature-dependent physical parameters. Results indicate that the temperature distribution depends strongly on the fluid conductivity and electric field magnitude, and particle deflection and trapping depend strongly on the channel geometry. Electrothermal (ET) effects perturb the EO flow field, creating vorticity near the channel constriction and enhancing the deflection and trapping effects. ET effects alter particle deflection and trapping responses in insulator-based dielectrophoresis devices, especially at intermediate device aspect ratios (2 ≤ r ≤ 7) in solutions of higher conductivity (σ m ≥ 1 × 10(-3)S/m). The impact of ET effects on particle deflection and trapping are diminished when particle EP mobility or channel EO mobility is high. In almost all cases, ET effects enhance negative dielectrophoretic particle deflection and trapping phenomena.
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Affiliation(s)
- Benjamin G Hawkins
- Department of Biomedical Engineering, College of Engineering, Cornell University, New York 14853, USA
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42
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Yilmaz G, Ciftlik AT, Külah H. A MEMS-based spiral channel dielectrophoretic chromatography system for cytometry applications. Biotechnol J 2010; 6:185-94. [PMID: 20949543 DOI: 10.1002/biot.201000204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 08/28/2010] [Accepted: 08/30/2010] [Indexed: 11/09/2022]
Abstract
In this paper design, fabrication, and evaluation of an easy-to-use and low cost dielectrophoretic quantizer are introduced. The device works with standard tools in a biomedical laboratory: a stereo microscope with CCD camera and a voltage supply. A novel spiral microchannel geometry together with the coaxial electrode configuration is established. The device works with a droplet of sample, eliminating microfluidic connections, and external syringes. The proposed geometry decreases the footprint, therefore reduces the device cost, without compromizing the separation and quantization performances. Coaxial electrode geometry enables continuous electric-field application with simple voltage supplies. The devices are fabricated using a simple 3-mask process, and experiments are realized with 1 and 10 μm polystyrene beads. The results show that 1 μm particles have an average speed of 4.57 μm/s with 1.06 μm/s SD, and 10 μm particles have an average speed of 544 μm/s with 105 μm/s SD. The speed variation coefficient for 1 and 10 μm beads can be calculated as 23 and 19%, respectively. The size accuracy of the device is ± 10%, while the resolution is 20%, i.e., particles with radii different from each other by 20% can be separated. Hence, moderate separation performance with minimized cost and standard laboratory equipment is enabled.
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Affiliation(s)
- Gürkan Yilmaz
- Electrical and Electronics Engineering Department, Middle East Technical University, Ankara, Turkey
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43
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Henning A, Bier FF, Hölzel R. Dielectrophoresis of DNA: Quantification by impedance measurements. BIOMICROFLUIDICS 2010; 4:022803. [PMID: 20697597 PMCID: PMC2917884 DOI: 10.1063/1.3430550] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Accepted: 04/27/2010] [Indexed: 05/12/2023]
Abstract
Dielectrophoretic properties of DNA have been determined by measuring capacitance changes between planar microelectrodes. DNA sizes ranged from 100 bp to 48 kbp, DNA concentrations from below 0.1 to 70 mugml. Dielectrophoretic spectra exhibited maximum response around 3 kHz and 3 MHz. The strongest response was found for very long DNA (above 10 kbp) and for short 100 bp fragments, which corresponds to the persistence length of DNA. The method allows for an uncomplicated, automatic acquisition of the dielectrophoretic properties of submicroscopical objects without the need for labeling protocols or optical accessibility.
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Affiliation(s)
- Anja Henning
- Fraunhofer Institute for Biomedical Engineering, D-14476 Potsdam, Germany
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44
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Khoshmanesh K, Zhang C, Tovar-Lopez FJ, Nahavandi S, Baratchi S, Kalantar-zadeh K, Mitchell A. Dielectrophoretic manipulation and separation of microparticles using curved microelectrodes. Electrophoresis 2009; 30:3707-17. [DOI: 10.1002/elps.200900079] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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45
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Improvements in the extraction of cell electric properties from their electrorotation spectrum. Bioelectrochemistry 2009; 79:25-30. [PMID: 19892606 DOI: 10.1016/j.bioelechem.2009.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 09/21/2009] [Accepted: 10/08/2009] [Indexed: 11/21/2022]
Abstract
In this paper, we propose a new approach to perform cell dielectric characterization from their electrorotation spectrum. At first, a variance analysis is carried out to quantify the dispersion in electrorotation spectra due to the different parameters involved. On this basis, the impact of each parameter is emphasized by weighing the spectrum with an appropriate frequency-dependent coefficient: this technique enables to minimize the coupling effects which deteriorate the accuracy of parameter extraction. In addition, the Nelder-Mead simplex algorithm used in the identification procedure is modified to account for bounded intervals in which the unknown parameters are expected to vary. Both these techniques have proven to give increased confidence levels compared to previous work reported in the literature.
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46
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Moon HS, Nam YW, Park JC, Jung HI. Dielectrophoretic separation of airborne microbes and dust particles using a microfluidic channel for real-time bioaerosol monitoring. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:5857-63. [PMID: 19731688 DOI: 10.1021/es900078z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Airborne microbes such as fungi, bacteria, and viruses are a threat to public health. Robust and real-time detection systems are necessary to prevent and control such dangerous biological particles in public places and dwellings. For direct and real-time detection of airborne microbes, samples must be collected and typically resuspended in liquid prior to detection; however, environmental particles such as dust are also trapped in such samples. Therefore, the isolation of target bacteria or a selective collection of microbes from unwanted nonbiological particles prior to detection is of great importance. Dielectrophoresis (DEP), the translational motion of charge neutral matter in nonuniform electric fields, is an emerging technique that can rapidly separate biological particles in microfluidics because low voltages produce significant and contactless forces on particles without any modification or labeling. In this paper, we propose a new method for the separation of airborne microbes using DEP with a simple and novel curved electrode design for separating bacteria in a solution containing beads or dust that are taken from an airborne environmental sample. Using this method, we successfully isolated 90% of the airborne bacterium Micrococcus luteus from a mixture of bacteria and dust using a microfluidic device, consisting of novel curved electrodes that attract bacteria and repel or leave dust particles. As there has been little research on analyzing environmental samples using microfluidics and DEP, this work describes a novel strategy for a rapid and direct bioaerosol monitoring system.
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Affiliation(s)
- Hui-Sung Moon
- Laboratory of Biochip Technology, School of Mechanical Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749, South Korea
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47
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Abstract
Weak electric currents generated using conductive electrodes have been shown to increase the efficacy of antibiotics against bacterial biofilms, a phenomenon termed "the bioelectric effect." The purposes of the present study were (i) to find out whether insulated electrodes that generate electric fields without "ohmic" electric currents, and thus are not associated with the formation of metal ions and free radicals, can inhibit the growth of planktonic bacteria and (ii) to define the parameters that are most effective against bacterial growth. The results obtained indicate that electric fields generated using insulated electrodes can inhibit the growth of planktonic Staphylococcus aureus and Pseudomonas aeruginosa and that the effect is amplitude and frequency dependent, with a maximum at 10 MHz. The combined effect of the electric field and chloramphenicol was found to be additive. Several possible mechanisms underlying the observed effect, as well as its potential clinical uses, are discussed.
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48
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Sabounchi P, Morales AM, Ponce P, Lee LP, Simmons BA, Davalos RV. Sample concentration and impedance detection on a microfluidic polymer chip. Biomed Microdevices 2008; 10:661-70. [DOI: 10.1007/s10544-008-9177-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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