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Jangra A, Shriyam S, Santiago JG, Bahga SS. A neural network model for rapid prediction of analyte focusing in isotachophoresis. Electrophoresis 2024; 45:599-608. [PMID: 38059796 DOI: 10.1002/elps.202300198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 11/14/2023] [Accepted: 11/20/2023] [Indexed: 12/08/2023]
Abstract
We present the development and demonstration of a neural network (NN) model for fast and accurate prediction of whether or not a chosen analyte is focused by an isotachophoresis (ITP) buffer system. The NN model is useful in the rapid evaluation of possible ITP chemistries applicable to analytes of interest. We trained and tested the NN model for univalent species based on extensive data sets of over 10,000 anionic and 10,000 cationic ITP simulations. The NN model uses as inputs the mobilities and the acid dissociation constants of leading electrolyte ion, trailing electrolyte ion, counterion, and a single analyte as well as the leading-to-counterion concentration ratio of the leading zone. The output then indicates whether the chosen electrolyte system yields stable ITP focusing of the analyte. The prediction accuracy of the NN model is over 97.7%. We demonstrate the applicability of the NN by validating its predictions with reported experimental data for anionic and cationic ITP. We have packaged the NN model in a free, web-based application named IONN (isotachophoresis on neural network), which can be used to rapidly screen ITP electrolyte systems.
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Affiliation(s)
- Amit Jangra
- Department of Mechanical Engineering, Indian Institute of Technology Delhi, New Delhi, India
- Government Polytechnic, Hisar, Haryana, India
| | - Shaurya Shriyam
- Department of Mechanical Engineering, Indian Institute of Technology Delhi, New Delhi, India
- Yardi School of Artificial Intelligence, Indian Institute of Technology Delhi, New Delhi, India
| | - Juan G Santiago
- Department of Mechanical Engineering, Stanford University, Stanford, California, USA
| | - Supreet Singh Bahga
- Department of Mechanical Engineering, Indian Institute of Technology Delhi, New Delhi, India
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2
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Gebhard F, Bonart H, Roy T, Meckel T, Hardt S. Isotachophoresis with Oscillating Sample Zones to Control the Spatial Overlap of Co-focused Species. Anal Chem 2024; 96:4446-4454. [PMID: 38451777 DOI: 10.1021/acs.analchem.3c04606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
Microfluidic isotachophoresis (ITP) is a powerful technique that can significantly increase the reaction rate of homogeneous chemical reactions by cofocusing reactants in a narrow sample zone. Correspondingly, ITP has been utilized to reduce the reaction time in various bioanalytical assays. However, in conventional ITP, it is hardly possible to control the reaction rate in real time, i.e., speeding up or slowing down a reaction on demand. Here, we experimentally demonstrate a new mode of ITP that allows the spatial overlap of two ITP zones to be precisely controlled over time, which is a crucial first step toward controlling reaction rates. Two nonreactive samples are initially focused and separated by a spacer using a DC electric field. By superimposing an oscillating field component with sufficiently high amplitude on the DC field, the spatial overlap of their concentration profiles is temporarily increased due to electromigration dispersion. The time-average of this overlap can be precisely controlled by varying the frequency and amplitude of the oscillation. We suggest that this scheme can be transferred to chemical reactions between ionic species with sufficiently different electrophoretic mobilities. Tuning the parameters of the oscillatory electric field should allow direct control of the corresponding reaction rate.
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Affiliation(s)
- Florian Gebhard
- Fachbereich Maschinenbau, Technische Universität Darmstadt, Peter-Grünberg-Str. 10, Darmstadt DE 64287, Germany
| | - Henning Bonart
- Fachbereich Maschinenbau, Technische Universität Darmstadt, Peter-Grünberg-Str. 10, Darmstadt DE 64287, Germany
| | - Tamal Roy
- Fachbereich Maschinenbau, Technische Universität Darmstadt, Peter-Grünberg-Str. 10, Darmstadt DE 64287, Germany
- Departement Maschinenbau und Verfahrenstechnik, Eidgenössische Technische Hochschule Zürich, Sonneggstrasse 3, Zürich CH8006, Switzerland
| | - Tobias Meckel
- Fachbereich Chemie, Technische Universität Darmstadt, Peter-Grünberg-Str. 8, Darmstadt DE 64287, Germany
| | - Steffen Hardt
- Fachbereich Maschinenbau, Technische Universität Darmstadt, Peter-Grünberg-Str. 10, Darmstadt DE 64287, Germany
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3
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Garg R, Maurya A, Mani NK, Prasad D. Thread-powered cell lysis and isotachophoresis: unlocking microbial DNA for diverse molecular applications. World J Microbiol Biotechnol 2024; 40:97. [PMID: 38349426 DOI: 10.1007/s11274-024-03906-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 01/22/2024] [Indexed: 02/15/2024]
Abstract
Central to the domain of molecular biology resides the foundational process of DNA extraction and purification, a cornerstone underpinning a myriad of pivotal applications. In this research, we introduce a DNA extraction and purification technique leveraging polypropylene (PP) threads. The process commences with robust cell lysis achieved through the vigorous agitation of interwoven PP threads. The friction between the threads facilitates cell lysis especially those microbes having tough cell wall. For purification of DNA, thread-based isotachophoresis was employed which makes the whole process swift and cost-effective. Lysed cell-laden threads were submerged in a trailing electrolyte which separated DNA from other cellular contents. The process was performed with a tailored ITP device. An electric field directs DNA, cell debris, trailing electrolyte, and leading electrolyte toward the anode. Distinct ion migration resulted in DNA concentrating on the PP thread's anode-proximal region. The SYBR green dye is used to visualize DNA as a prominent green zone under blue light. The purified DNA exhibits high purity levels of 1.82 ± 0.1 (A260/A280), making it suitable for various applications aiming at nucleic acid detection.
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Affiliation(s)
- Rishabh Garg
- Department of Bioengineering and Biotechnology, Birla Institute of Technology, Mesra, Jharkhand, 835215, India
| | - Aharnish Maurya
- Department of Bioengineering and Biotechnology, Birla Institute of Technology, Mesra, Jharkhand, 835215, India
| | - Naresh Kumar Mani
- Microfluidics, Sensors and Diagnostics (μSenD) Laboratory, Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Dinesh Prasad
- Department of Bioengineering and Biotechnology, Birla Institute of Technology, Mesra, Jharkhand, 835215, India.
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Kašička V. Recent developments in capillary and microchip electroseparations of peptides (2021-mid-2023). Electrophoresis 2024; 45:165-198. [PMID: 37670208 DOI: 10.1002/elps.202300152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 08/22/2023] [Accepted: 08/22/2023] [Indexed: 09/07/2023]
Abstract
This review article brings a comprehensive survey of developments and applications of high-performance capillary and microchip electromigration methods (zone electrophoresis in a free solution or in sieving media, isotachophoresis, isoelectric focusing, affinity electrophoresis, electrokinetic chromatography, and electrochromatography) for analysis, micropreparation, and physicochemical characterization of peptides in the period from 2021 up to ca. the middle of 2023. Progress in the study of electromigration properties of peptides and various aspects of their analysis, such as sample preparation, adsorption suppression, electroosmotic flow regulation, and detection, are presented. New developments in the particular capillary electromigration methods are demonstrated, and several types of their applications are reported. They cover qualitative and quantitative analysis of synthetic or isolated peptides and determination of peptides in complex biomatrices, peptide profiling of biofluids and tissues, and monitoring of chemical and enzymatic reactions and physicochemical changes of peptides. They include also amino acid and sequence analysis of peptides, peptide mapping of proteins, separation of stereoisomers of peptides, and their chiral analyses. In addition, micropreparative separations and physicochemical characterization of peptides and their interactions with other (bio)molecules by the above CE methods are described.
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Affiliation(s)
- Václav Kašička
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czechia
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Sena-Torralba A, Banguera-Ordoñez YD, Mira-Pascual L, Maquieira Á, Morais S. Exploring the potential of paper-based electrokinetic phenomena in PoC biosensing. Trends Biotechnol 2023; 41:1299-1313. [PMID: 37150668 DOI: 10.1016/j.tibtech.2023.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/06/2023] [Accepted: 04/14/2023] [Indexed: 05/09/2023]
Abstract
In order to decentralize health care, the development of point-of-care (PoC) assays has gained significant attention in recent decades. The lateral flow immunoassay (LFIA) has emerged as a promising bioanalytical method due to its low cost and single-step detection process. However, its limited sensitivity and inability to detect disease biomarkers at clinically relevant levels have hindered its application for early diagnosis. This review explores the potential of merging different electrokinetic phenomena into paper-based assays to enhance their analytical performance, offering a versatile and affordable approach for PoC testing. The review exposes the challenges faced in integrating electrokinetic phenomena with paper-based biosensing and concludes by discussing the issues that need to be improved to maximize the potential of this technology for early diagnosis.
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Affiliation(s)
- Amadeo Sena-Torralba
- Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM), Universitat Politècnica de València, Universitat de València, Camino de Vera s/n, 46022, Valencia, Spain; Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
| | - Yulieth D Banguera-Ordoñez
- Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM), Universitat Politècnica de València, Universitat de València, Camino de Vera s/n, 46022, Valencia, Spain
| | - Laia Mira-Pascual
- Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM), Universitat Politècnica de València, Universitat de València, Camino de Vera s/n, 46022, Valencia, Spain
| | - Ángel Maquieira
- Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM), Universitat Politècnica de València, Universitat de València, Camino de Vera s/n, 46022, Valencia, Spain; Departamento de Química, Universitat Politècnica de València, Camino de Vera s/n, 46022, Valencia, Spain
| | - Sergi Morais
- Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM), Universitat Politècnica de València, Universitat de València, Camino de Vera s/n, 46022, Valencia, Spain; Departamento de Química, Universitat Politècnica de València, Camino de Vera s/n, 46022, Valencia, Spain.
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Hemmateenejad B, Rafatmah E, Shojaeifard Z. Microfluidic paper and thread-based separations: Chromatography and electrophoresis. J Chromatogr A 2023; 1704:464117. [PMID: 37300912 DOI: 10.1016/j.chroma.2023.464117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/25/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023]
Abstract
Paper and thread are widely used as the substrates for fabricating low-cost, disposable, and portable microfluidic analytical devices used in clinical, environmental, and food safety monitoring. Concerning separation methods including chromatography and electrophoresis, these substrates provide unique platforms for developing portable devices. This review focuses on summarizing recent research on the miniaturization of the separation techniques using paper and thread. Preconcentration, purification, desalination, and separation of various analytes are achievable using electrophoresis and chromatography methods integrated with modified or unmodified paper/thread wicking channels. A variety of 2D and 3D designs of paper/thread platforms for zone electrophoresis, capillary electrophoresis, and modified/unmodified chromatography are discussed with emphasis on their limitation and improvements. The current progress in the signal amplification strategies such as isoelectric focusing, isotachophoresis, ion concentration polarization, isoelectric focusing, and stacking methods in paper-based devices are reviewed. Different strategies for chromatographic separations based on paper/thread will be explained. The separation of target species from complex samples and their determination by integration with other analytical methods like spectroscopy and electrochemistry are well-listed. Furthermore, the innovations for plasma and cell separation from blood as an important human biofluid are presented, and the related paper/thread modification methods are explored.
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Bonart H, Gebhard F, Hecht L, Roy T, Liebchen B, Hardt S. Detecting Isotachophoresis Zones Hidden in Noise Using Signal Processing. Anal Chem 2023; 95:7575-7583. [PMID: 37133530 DOI: 10.1021/acs.analchem.3c00321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Lowering the limit of detection in chemical or biochemical analysis is key to extending the application scope of sensing schemes. Usually, this is related to an increased instrumentation effort, which in turn precludes many commercial applications. We demonstrate that the signal-to-noise ratio of isotachophoresis-based microfluidic sensing schemes can be substantially increased merely by postprocessing of recorded signals. This becomes possible by exploiting knowledge about the physics of the underlying measurement process. The implementation of our method is based on microfluidic isotachophoresis and fluorescence detection, for which we take advantage of the physics of electrophoretic sample transport and the structure of noise in the imaging process. We demonstrate that by processing only 200 images, the detectable concentration, compared to the detection from a single image, is already lowered by 2 orders of magnitude without any additional instrumentation effort. Furthermore, we show that the signal-to-noise ratio is proportional to the square root of the number of fluorescence images, which leaves room for further lowering of the detection limit. In the future, our results could be relevant for various applications where the detection of minute sample amounts plays a role.
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Affiliation(s)
- Henning Bonart
- Technische Universität Darmstadt, Department of Mechanical Engineering, Institute for Nano- and Microfluidics, Alarich-Weiss-Straße 10, 64287 Darmstadt, Germany
- Technische Universität Darmstadt, Center for Computational Engineering, Dolivostraße 15, 64293 Darmstadt, Germany
| | - Florian Gebhard
- Technische Universität Darmstadt, Department of Mechanical Engineering, Institute for Nano- and Microfluidics, Alarich-Weiss-Straße 10, 64287 Darmstadt, Germany
| | - Lukas Hecht
- Technische Universität Darmstadt, Department of Physics, Institute for Condensed Matter Physics, Hochschulstraße 8, 64289 Darmstadt, Germany
| | - Tamal Roy
- Technische Universität Darmstadt, Department of Mechanical Engineering, Institute for Nano- and Microfluidics, Alarich-Weiss-Straße 10, 64287 Darmstadt, Germany
- Eidgenössische Technische Hochschule Zürich, Department of Mechanical and Process Engineering, Sonneggstrasse 3, Zurich 8092, Switzerland
| | - Benno Liebchen
- Technische Universität Darmstadt, Department of Physics, Institute for Condensed Matter Physics, Hochschulstraße 8, 64289 Darmstadt, Germany
| | - Steffen Hardt
- Technische Universität Darmstadt, Department of Mechanical Engineering, Institute for Nano- and Microfluidics, Alarich-Weiss-Straße 10, 64287 Darmstadt, Germany
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Avaro AS, Santiago JG. A critical review of microfluidic systems for CRISPR assays. LAB ON A CHIP 2023; 23:938-963. [PMID: 36601854 DOI: 10.1039/d2lc00852a] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Reviewed are nucleic acid detection assays that incorporate clustered regularly interspaced short palindromic repeats (CRISPR)-based diagnostics and microfluidic devices and techniques. The review serves as a reference for researchers who wish to use CRISPR-Cas systems for diagnostics in microfluidic devices. The review is organized in sections reflecting a basic five-step workflow common to most CRISPR-based assays. These steps are analyte extraction, pre-amplification, target recognition, transduction, and detection. The systems described include custom microfluidic chips and custom (benchtop) chip control devices for automated assays steps. Also included are partition formats for digital assays and lateral flow biosensors as a readout modality. CRISPR-based, microfluidics-driven assays offer highly specific detection and are compatible with parallel, combinatorial implementation. They are highly reconfigurable, and assays are compatible with isothermal and even room temperature operation. A major drawback of these assays is the fact that reports of kinetic rates of these enzymes have been highly inconsistent (many demonstrably erroneous), and the low kinetic rate activity of these enzymes limits achievable sensitivity without pre-amplification. Further, the current state-of-the-art of CRISPR assays is such that nearly all systems rely on off-chip assays steps, particularly off-chip sample preparation.
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Affiliation(s)
- Alexandre S Avaro
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA.
| | - Juan G Santiago
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA.
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Choubey A, Dubey K, Bahga SS. Rapid prototyping of polydimethylsiloxane (PDMS) microchips using electrohydrodynamic jet printing: Application to electrokinetic assays. Electrophoresis 2023; 44:725-732. [PMID: 36774545 DOI: 10.1002/elps.202200241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 02/13/2023]
Abstract
Polydimethylsiloxane (PDMS) based microfluidic devices have found increasing utility for electrophoretic and electrokinetic assays because of their ease of fabrication using replica molding. However, the fabrication of high-resolution molds for replica molding still requires the resource-intensive and time-consuming photolithography process, which precludes quick design iterations and device optimization. We here demonstrate a low-cost, rapid microfabrication process, based on electrohydrodynamic jet printing (EJP), for fabricating non-sacrificial master molds for replica molding of PDMS microfluidic devices. The method is based on the precise deposition of an electrically stretched polymeric solution of polycaprolactone in acetic acid on a silicon wafer placed on a computer-controlled motion stage. This process offers the high-resolution (order 10 μ $\umu$ m) capability of photolithography and rapid prototyping capability of inkjet printing to print high-resolution templates for elastomeric microfluidic devices within a few minutes. Through proper selection of the operating parameters such as solution flow rate, applied electric field, and stage speed, we demonstrate microfabrication of intricate master molds and corresponding PDMS microfluidic devices for electrokinetic applications. We demonstrate the utility of the fabricated PDMS microchips for nonlinear electrokinetic processes such as electrokinetic instability and controlled sample splitting in ITP. The ability to rapid prototype customized reusable master molds with order 10 μ $\umu$ m resolution within a few minutes can help in designing and optimizing microfluidic devices for various electrokinetic applications.
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Affiliation(s)
- Anupam Choubey
- Department of Mechanical Engineering, Indian Institute of Technology Delhi, New Delhi, India
| | - Kaushlendra Dubey
- Department of Mechanical Engineering, Indian Institute of Technology Delhi, New Delhi, India
| | - Supreet Singh Bahga
- Department of Mechanical Engineering, Indian Institute of Technology Delhi, New Delhi, India
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Doria S, Gagnon Z. Continuous Molecular Concentration and Separation Using Pulsed-Field Conductive-Wall Single-Buffer Teı́chophoresis. Anal Chem 2022; 94:13481-13488. [PMID: 36121349 DOI: 10.1021/acs.analchem.2c02608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present an experimental study of a novel continuous electrokinetic molecular concentration and separation technique termed teı́chophoresis (TPE). We demonstrate here that TPE can serve as a potential alternative to the electrokinetic method isotachophoresis (ITP). In ITP, an electric field serves to focus charged species between a low-mobility terminating electrolyte (TE) and a high-mobility leading electrolyte (LE). Similarly, TPE serves to focus charged species between a low-mobility TE; however, the LE is conveniently replaced with a no-flux boundary generated by a conductive wall. The electric field can still penetrate this no-flux region due to the wall's finite conductivity, but ion migration is impeded due to the physicality of the wall. We perform detailed concentration and separation experiments across varying electric potentials, flow rates, and TE concentrations. We also show that TPE can achieve a 60,000-fold concentration factor continuously without an LE, using only 10 V DC. In comparison with conventional batch-driven ITP, continuous free-flow wall TPE (FFTPE) has the potential to serve as a simplified alternative method. FFTPE offers a high concentration power at a fraction of the required voltage, does not require an LE, and has the increased throughput potential of a continuous process.
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Affiliation(s)
- Steven Doria
- Department of Chemical Engineering, Texas A&M University, 201 Jack E. Brown Building, College Station, Texas 77843, United States
| | - Zachary Gagnon
- Department of Chemical Engineering, Texas A&M University, 201 Jack E. Brown Building, College Station, Texas 77843, United States
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