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Wu Y, Yue Y, Zhang H, Ma X, Zhang Z, Li K, Meng Y, Wang S, Wang X, Huang W. Three-dimensional rotation of deformable cells at a bipolar electrode array using a rotating electric field. LAB ON A CHIP 2024; 24:933-945. [PMID: 38273814 DOI: 10.1039/d3lc00882g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2024]
Abstract
Three-dimensional rotation of cells is imperative in a variety of applications such as biology, medicine, and chemistry. We report for the first time a versatile approach for executing controllable 3D rotation of cells or particles at a bipolar electrode (BPE) array using a rotating electric field. The versatility of this method is demonstrated by 3D rotating various cells including yeast cells and K562 cells and the cells can be rotated to a desired orientation and immobilized for further operations. Our results demonstrate how electrorotation torque, induced charge electroosmosis (ICEO) flow and dielectrophoresis can be exerted on certain cells for modulating the rotation axis, speed, and direction. ICEO-based out-of-plane rotation is capable of rotating various cells in a vertical plane regardless of their shape and size. It can realize cell orientation by rotating cells toward a specific angle and enable cell rotation by steadily rotating multiple cells at a controllable speed. The rotation spectrum for in-plane rotation is further used to extract the cellular dielectric properties. This work offers a flexible method for controllable, contactless and precise rotation of different cells or particles, offering a rapid, high-throughput, and nondestructive rotation method for cell analysis and drug discovery.
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Affiliation(s)
- Yupan Wu
- School of Microelectronics, Northwestern Polytechnical University, Xi'an, 710072, PR China
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, China.
- Research & Development Institute of Northwestern Polytechnical University in Shenzhen, 518000, PR China
- Yangtze River Delta Research Institute of NPU, Taicang, 215400, PR China
| | - Yuanbo Yue
- School of Microelectronics, Northwestern Polytechnical University, Xi'an, 710072, PR China
| | - Haohao Zhang
- School of Microelectronics, Northwestern Polytechnical University, Xi'an, 710072, PR China
| | - Xun Ma
- School of Microelectronics, Northwestern Polytechnical University, Xi'an, 710072, PR China
| | - Zhexin Zhang
- School of Microelectronics, Northwestern Polytechnical University, Xi'an, 710072, PR China
| | - Kemu Li
- School of Microelectronics, Northwestern Polytechnical University, Xi'an, 710072, PR China
| | - Yingqi Meng
- School of Microelectronics, Northwestern Polytechnical University, Xi'an, 710072, PR China
| | - Shaoxi Wang
- School of Microelectronics, Northwestern Polytechnical University, Xi'an, 710072, PR China
| | - Xuewen Wang
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, China.
| | - Wei Huang
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, China.
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2
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Derakhshan R, Ramiar A, Ghasemi A. Continuous size-based DEP separation of particles using a bi-gap electrode pair. Analyst 2022; 147:5395-5408. [DOI: 10.1039/d2an01308h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The design, fabrication, and characterization of an advanced microfluidic device containing a bi-gap electrode pair for the continuous separation of three different populations of particles based on their size using DEP are presented.
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Affiliation(s)
- Reza Derakhshan
- PhD Student, Mechanical Engineering Department, Microfluidics and MEMS lab, Babol Noshirvani University of Technology, Babol, Iran
| | - Abas Ramiar
- Associate professor, Faculty of Mechanical Engineering, Microfluidics and MEMS lab, Babol Noshirvani University of Technology, Babol, Iran
| | - Amirhosein Ghasemi
- PhD, Mechanical Engineering Department, Microfluidics and MEMS lab, Babol Noshirvani University of Technology, Babol, Iran
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3
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Shi L, Esfandiari L. Emerging on-chip electrokinetic based technologies for purification of circulating cancer biomarkers towards liquid biopsy: A review. Electrophoresis 2021; 43:288-308. [PMID: 34791687 DOI: 10.1002/elps.202100234] [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] [Received: 08/02/2021] [Revised: 11/12/2021] [Accepted: 11/12/2021] [Indexed: 12/11/2022]
Abstract
Early detection of cancer can significantly reduce mortality and save lives. However, the current cancer diagnosis is highly dependent on costly, complex, and invasive procedures. Thus, a great deal of effort has been devoted to exploring new technologies based on liquid biopsy. Since liquid biopsy relies on detection of circulating biomarkers from biofluids, it is critical to isolate highly purified cancer-related biomarkers, including circulating tumor cells (CTCs), cell-free nucleic acids (cell-free DNA and cell-free RNA), small extracellular vesicles (exosomes), and proteins. The current clinical purification techniques are facing a number of drawbacks including low purity, long processing time, high cost, and difficulties in standardization. Here, we review a promising solution, on-chip electrokinetic-based methods, that have the advantage of small sample volume requirement, minimal damage to the biomarkers, rapid, and label-free criteria. We have also discussed the existing challenges of current on-chip electrokinetic technologies and suggested potential solutions that may be worthy of future studies.
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Affiliation(s)
- Leilei Shi
- Department of Electrical Engineering and Computer Science, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, Ohio, USA
| | - Leyla Esfandiari
- Department of Electrical Engineering and Computer Science, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, Ohio, USA.,Department of Biomedical Engineering, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, Ohio, USA
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Diaz-Armas GG, Cervantes-Gonzalez AP, Martinez-Duarte R, Perez-Gonzalez VH. Electrically driven microfluidic platforms for exosome manipulation and characterization. Electrophoresis 2021; 43:327-339. [PMID: 34717000 DOI: 10.1002/elps.202100202] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 10/06/2021] [Accepted: 10/25/2021] [Indexed: 01/15/2023]
Abstract
Exosomes are small extracellular vesicles that can be obtained from several body fluids such as blood and urine. Since these vesicles can carry biomarkers and other cargo, they have application in healthcare diagnostics and therapeutics, such as liquid biopsies and drug delivery. Yet, their identification and separation from a sample remain challenging due to their high degree of heterogeneity and their co-existence with other bioparticles. In this contribution, we review the state-of-the-art on electrical techniques and methods to displace, selectively trap/isolate, and detect/characterize exosomes in microfluidic devices. Although there are many reviews focused on exosome separation using benchtop equipment, such as ultracentrifugation, there are limited reviews focusing on the use of electrical phenomena in microfluidic devices for exosome manipulation and detection. Here, we highlight contributions published during the past decade and present perspectives for this research field for the near future, outlining challenges to address in years to come.
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Affiliation(s)
- Gladys G Diaz-Armas
- Tecnologico de Monterrey, School of Engineering and Sciences, Monterrey, Mexico
| | | | - Rodrigo Martinez-Duarte
- Multiscale Manufacturing Laboratory, Department of Mechanical Engineering, Clemson University, Clemson, South Carolina, USA
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5
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Electrokinetics couples with the adsorption of activated carbon-supported hydroxycarbonate green rust that enhances the removal of Sr cations from the stock solution in batch and column. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.118531] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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6
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Huang T, Song D, Chen X, Cao J, Jin JX, Liu W, Zhang SW, Liu LF, Yang CH, Zhou L, Xu J. A green rust-coated expanded perlite particle electrode-based adsorption coupling with the three-dimensional electrokinetics that enhances hexavalent chromium removal. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 213:112003. [PMID: 33588188 DOI: 10.1016/j.ecoenv.2021.112003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/23/2021] [Accepted: 01/26/2021] [Indexed: 06/12/2023]
Abstract
A green rust-coated expanded perlite (GR-coated Exp-p) microelectrode was synthesized and incorporated into a column-mode three-dimensional electrokinetic (3D-EK) platform to effectively pursue a continuous Cr(VI) removal from the aqueous solution. Brucite-like layers of GR were decorated onto the Exp-p material. The molar ratio of Fe(II) to Fe(III) played a most vital role among the three synthesis factors in influencing the performance of the particle electrode. For the equilibrium adsorption experiments, the target maximum adsorption capacity of 122 mg/g was predicted by a target optimizer and desirability function at the conditions following the pH of 4.7, the initial concentration of 172.4 mg/L, the dosage of 0.28 g/L, and the temperature of 28.96 °C, respectively. SO42-, Cl-, and NO3- fiercely competed with Cr(VI) anions in the acidic conditions for the locally positive sites. A low concentration and a slow flow were favored in the column-mode 3D-EK platform. The pseudo-first-order and Langmuir models were suitable for describing the kinetics and isotherms of the adsorption process, respectively. Cr(VI) anions were electrostatically attracted to the silanol groups and GR surface of the adsorbent, subsequently reduced in both heterogeneity and homogeneity, and finally immobilized by coordinating with silanediol groups and silanetriol groups.
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Affiliation(s)
- Tao Huang
- School of Chemistry and Materials Engineering, Changshu Institute of Technology, No. 99, South 3rd Ring Road, Changshu 215500, China; Suzhou Key Laboratory of Functional Ceramic Materials, Changshu Institute of Technology, Changshu 215500, China; School of Chemical Engineering & Technology, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
| | - Dongping Song
- School of Chemistry and Materials Engineering, Changshu Institute of Technology, No. 99, South 3rd Ring Road, Changshu 215500, China.
| | - Xiangping Chen
- School of Chemistry and Materials Engineering, Changshu Institute of Technology, No. 99, South 3rd Ring Road, Changshu 215500, China
| | - Jun Cao
- School of Chemistry and Materials Engineering, Changshu Institute of Technology, No. 99, South 3rd Ring Road, Changshu 215500, China
| | - Jun-Xun Jin
- School of Chemistry and Materials Engineering, Changshu Institute of Technology, No. 99, South 3rd Ring Road, Changshu 215500, China
| | - Wanhui Liu
- School of Chemistry and Materials Engineering, Changshu Institute of Technology, No. 99, South 3rd Ring Road, Changshu 215500, China; Suzhou Key Laboratory of Functional Ceramic Materials, Changshu Institute of Technology, Changshu 215500, China
| | - Shu-Wen Zhang
- Nuclear Resources Engineering College, University of South China, 421001, China
| | - Long-Fei Liu
- School of Chemistry and Materials Engineering, Changshu Institute of Technology, No. 99, South 3rd Ring Road, Changshu 215500, China; Suzhou Key Laboratory of Functional Ceramic Materials, Changshu Institute of Technology, Changshu 215500, China
| | - Chun-Hai Yang
- School of Chemistry and Materials Engineering, Changshu Institute of Technology, No. 99, South 3rd Ring Road, Changshu 215500, China; Suzhou Key Laboratory of Functional Ceramic Materials, Changshu Institute of Technology, Changshu 215500, China
| | - Lulu Zhou
- School of Chemistry and Materials Engineering, Changshu Institute of Technology, No. 99, South 3rd Ring Road, Changshu 215500, China
| | - Jiaojiao Xu
- School of Chemistry and Materials Engineering, Changshu Institute of Technology, No. 99, South 3rd Ring Road, Changshu 215500, China
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Li Y, Wang Y, Wan K, Wu M, Guo L, Liu X, Wei G. On the design, functions, and biomedical applications of high-throughput dielectrophoretic micro-/nanoplatforms: a review. NANOSCALE 2021; 13:4330-4358. [PMID: 33620368 DOI: 10.1039/d0nr08892g] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
As an efficient, rapid and label-free micro-/nanoparticle separation technique, dielectrophoresis (DEP) has attracted widespread attention in recent years, especially in the field of biomedicine, which exhibits huge potential in biomedically relevant applications such as disease diagnosis, cancer cell screening, biosensing, and others. DEP technology has been greatly developed recently from the low-flux laboratory level to high-throughput practical applications. In this review, we summarize the recent progress of DEP technology in biomedical applications, including firstly the design of various types and materials of DEP electrode and flow channel, design of input signals, and other improved designs. Then, functional tailoring of DEP systems with endowed specific functions including separation, purification, capture, enrichment and connection of biosamples, as well as the integration of multifunctions, are demonstrated. After that, representative DEP biomedical application examples in aspects of disease detection, drug synthesis and screening, biosensing and cell positioning are presented. Finally, limitations of existing DEP platforms on biomedical application are discussed, in which emphasis is given to the impact of other electrodynamic effects such as electrophoresis (EP), electroosmosis (EO) and electrothermal (ET) effects on DEP efficiency. This article aims to provide new ideas for the design of novel DEP micro-/nanoplatforms with desirable high throughput toward application in the biomedical community.
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Affiliation(s)
- Yalin Li
- College of Chemistry and Chemical Engineering, Qingdao University, 266071 Qingdao, PR China.
| | - Yan Wang
- College of Chemistry and Chemical Engineering, Qingdao University, 266071 Qingdao, PR China.
| | - Keming Wan
- College of Chemistry and Chemical Engineering, Qingdao University, 266071 Qingdao, PR China.
| | - Mingxue Wu
- College of Chemistry and Chemical Engineering, Qingdao University, 266071 Qingdao, PR China.
| | - Lei Guo
- Research Center for High-Value Utilization of Waste Biomass, College of Life Science, College of Life Science, Qingdao University, 266071 Qingdao, PR China
| | - Xiaomin Liu
- College of Chemistry and Chemical Engineering, Qingdao University, 266071 Qingdao, PR China.
| | - Gang Wei
- College of Chemistry and Chemical Engineering, Qingdao University, 266071 Qingdao, PR China.
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8
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Liu Y, Hayes MA. Orders-of-Magnitude Larger Force Demonstrated for Dielectrophoresis of Proteins Enabling High-Resolution Separations Based on New Mechanisms. Anal Chem 2020; 93:1352-1359. [DOI: 10.1021/acs.analchem.0c02763] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Yameng Liu
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Mark A. Hayes
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, United States
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An Approach to Ring Resonator Biosensing Assisted by Dielectrophoresis: Design, Simulation and Fabrication. MICROMACHINES 2020; 11:mi11110954. [PMID: 33105846 PMCID: PMC7690605 DOI: 10.3390/mi11110954] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 12/12/2022]
Abstract
The combination of extreme miniaturization with a high sensitivity and the potential to be integrated in an array form on a chip has made silicon-based photonic microring resonators a very attractive research topic. As biosensors are approaching the nanoscale, analyte mass transfer and bonding kinetics have been ascribed as crucial factors that limit their performance. One solution may be a system that applies dielectrophoretic forces, in addition to microfluidics, to overcome the diffusion limits of conventional biosensors. Dielectrophoresis, which involves the migration of polarized dielectric particles in a non-uniform alternating electric field, has previously been successfully applied to achieve a 1000-fold improved detection efficiency in nanopore sensing and may significantly increase the sensitivity in microring resonator biosensing. In the current work, we designed microring resonators with integrated electrodes next to the sensor surface that may be used to explore the effect of dielectrophoresis. The chip design, including two different electrode configurations, electric field gradient simulations, and the fabrication process flow of a dielectrohoresis-enhanced microring resonator-based sensor, is presented in this paper. Finite element method (FEM) simulations calculated for both electrode configurations revealed ∇E2 values above 1017 V2m−3 around the sensing areas. This is comparable to electric field gradients previously reported for successful interactions with larger molecules, such as proteins and antibodies.
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11
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Pesch GR, Du F. A review of dielectrophoretic separation and classification of non-biological particles. Electrophoresis 2020; 42:134-152. [PMID: 32667696 DOI: 10.1002/elps.202000137] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/08/2020] [Accepted: 07/08/2020] [Indexed: 02/06/2023]
Abstract
Dielectrophoresis (DEP) is a selective electrokinetic particle manipulation technology that is applied for almost 100 years and currently finds most applications in biomedical research using microfluidic devices operating at moderate to low throughput. This paper reviews DEP separators capable of high-throughput operation and research addressing separation and analysis of non-biological particle systems. Apart from discussing particle polarization mechanisms, this review summarizes the early applications of DEP for dielectric sorting of minerals and lists contemporary applications in solid/liquid, liquid/liquid, and solid/air separation, for example, DEP filtration or airborne fiber length classification; the review also summarizes developments in DEP fouling suppression, gives a brief overview of electrocoalescence and addresses current problems in high-throughput DEP separation. We aim to provide inspiration for DEP application schemes outside of the biomedical sector, for example, for the recovery of precious metal from scrap or for extraction of metal from low-grade ore.
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Affiliation(s)
- Georg R Pesch
- Faculty of Production Engineering, Chemical Process Engineering Group, University of Bremen, Bremen, Germany
| | - Fei Du
- Faculty of Production Engineering, Chemical Process Engineering Group, University of Bremen, Bremen, Germany
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12
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Hayes MA. Dielectrophoresis of proteins: experimental data and evolving theory. Anal Bioanal Chem 2020; 412:3801-3811. [PMID: 32314000 PMCID: PMC7250158 DOI: 10.1007/s00216-020-02623-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 02/28/2020] [Accepted: 03/27/2020] [Indexed: 02/07/2023]
Abstract
The ability to selectively move and trap proteins is core to their effective use as building blocks and for their characterization. Analytical and preparative strategies for proteins have been pursued and modeled for nearly a hundred years, with great advances and success. Core to all of these studies is the separation, isolation, purification, and concentration of pure homogeneous fractions of a specific protein in solution. Processes to accomplish this useful solution include biphasic equilibrium (chromatographies, extractions), mechanical, bulk property, chemical equilibria, and molecular recognition. Ultimately, the goal of all of these is to physically remove all non-like protein molecules-to the finest detail: all atoms in the full three-dimensional structure being identical down the chemical bond and bulk structure chirality. One strategy which has not been effectively pursued is exploiting the higher order subtle electrical properties of the protein-solvent system. The advent of microfluidic systems has enabled the use of very high electric fields and well-defined gradients such that extremely high resolution separations of protein mixtures are possible. These advances and recognition of these capabilities have caused a re-evaluation of the underlying theoretical models and they were found to be inadequate. New theoretical descriptions are being considered which align more closely to the total forces present and the subtlety of differences between similar proteins. These are focused on the interfacial area between the protein and hydrating solvent molecules, as opposed to the macroscale assumptions of homogeneous solutions and particles. This critical review examines all data which has been published that place proteins in electric field gradients which induce collection of those proteins, demonstrating a force greater than dispersive effects or countering forces. Evolving theoretical constructs are presented and discussed, and a general estimate of future capabilities using the higher order effects and the high fields and precise gradients of microfluidic systems is discussed. Graphical abstract.
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Affiliation(s)
- Mark A Hayes
- School of Molecular Sciences, Arizona State University, Mail Stop 1604, Tempe, AZ, 85287, USA.
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Rabbani MT, Sonker M, Ros A. Carbon nanotube dielectrophoresis: Theory and applications. Electrophoresis 2020; 41:1893-1914. [PMID: 32474942 DOI: 10.1002/elps.202000049] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/07/2020] [Accepted: 05/18/2020] [Indexed: 01/31/2023]
Abstract
Carbon nanotubes (CNTs) are one of the most extensively studied nanomaterials in the 21st century. Since their discovery in 1991, many studies have been reported advancing our knowledge in terms of their structure, properties, synthesis, and applications. CNTs exhibit unique electrothermal and conductive properties which, combined with their mechanical strength, have led to tremendous attention of CNTs as a nanoscale material in the past two decades. To introduce the various types of CNTs, we first provide basic information on their structure followed by some intriguing properties and a brief overview of synthesis methods. Although impressive advances have been demonstrated with CNTs, critical applications require purification, positioning, and separation to yield desired properties and functional elements. Here, we review a versatile technique to manipulate CNTs based on their dielectric properties, namely dielectrophoresis (DEP). A detailed discussion on the DEP aspects of CNTs including the theory and various technical microfluidic realizations is provided. Various advancements in DEP-based manipulations of single-walled and multiwalled CNTs are also discussed with special emphasis on applications involving separation, purification, sensing, and nanofabrication.
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Affiliation(s)
- Mohammad Towshif Rabbani
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA.,Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Mukul Sonker
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA.,Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Alexandra Ros
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA.,Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, USA
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Hölzel R, Pethig R. Protein Dielectrophoresis: I. Status of Experiments and an Empirical Theory. MICROMACHINES 2020; 11:E533. [PMID: 32456059 PMCID: PMC7281080 DOI: 10.3390/mi11050533] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 05/20/2020] [Accepted: 05/20/2020] [Indexed: 12/04/2022]
Abstract
The dielectrophoresis (DEP) data reported in the literature since 1994 for 22 different globular proteins is examined in detail. Apart from three cases, all of the reported protein DEP experiments employed a gradient field factor ∇Em2 that is much smaller (in some instances by many orders of magnitude) than the ~4 1021 V2/m3 required, according to current DEP theory, to overcome the dispersive forces associated with Brownian motion. This failing results from the macroscopic Clausius-Mossotti (CM) factor being restricted to the range 1.0 > CM > -0.5. Current DEP theory precludes the protein's permanent dipole moment (rather than the induced moment) from contributing to the DEP force. Based on the magnitude of the β-dispersion exhibited by globular proteins in the frequency range 1 kHz-50 MHz, an empirically derived molecular version of CM is obtained. This factor varies greatly in magnitude from protein to protein (e.g., ~37,000 for carboxypeptidase; ~190 for phospholipase) and when incorporated into the basic expression for the DEP force brings most of the reported protein DEP above the minimum required to overcome dispersive Brownian thermal effects. We believe this empirically-derived finding validates the theories currently being advanced by Matyushov and co-workers.
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Affiliation(s)
- Ralph Hölzel
- Fraunhofer Institute for Cell Therapy and Immunology, Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam-Golm, Germany;
| | - Ronald Pethig
- School of Engineering, Institute for Integrated Micro and Nanosystems, University of Edinburgh, The King’s Buildings, Edinburgh EH9 3JF, UK
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15
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Affiliation(s)
- Daihyun Kim
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
| | - Mukul Sonker
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
| | - Alexandra Ros
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
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