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Ahmadi F, Tran H, Letourneau N, Little SR, Fortin A, Moraitis AN, Shih SCC. An Automated Single-Cell Droplet-Digital Microfluidic Platform for Monoclonal Antibody Discovery. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2308950. [PMID: 38441226 DOI: 10.1002/smll.202308950] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 01/30/2024] [Indexed: 06/27/2024]
Abstract
Monoclonal antibody (mAb) discovery plays a prominent role in diagnostic and therapeutic applications. Droplet microfluidics has become a standard technology for high-throughput screening of antibody-producing cells due to high droplet single-cell confinement frequency and rapid analysis and sorting of the cells of interest with their secreted mAbs. In this work, a new method is described for on-demand co-encapsulation of cells that eliminates the difficulties associated with washing in between consecutive steps inside the droplets and enables the washing and addition of fresh media. The new platform identifies hybridoma cells that are expressing antibodies of interest using antibody-characterization assays to find the best-performing or rare-cell antibody candidates.
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Affiliation(s)
- Fatemeh Ahmadi
- Department of Electrical and Computer Engineering, Concordia University, 1455 de Maisonneuve Blvd. West, Montréal, Québec, H3G 1M8, Canada
- Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke Street West, Montréal, Québec, H4B 1R6, Canada
| | - Hao Tran
- Department of Electrical and Computer Engineering, Concordia University, 1455 de Maisonneuve Blvd. West, Montréal, Québec, H3G 1M8, Canada
| | - Natasha Letourneau
- Department of Biology, Concordia University, 7141 Sherbrooke Street West, Montréal, Québec, H4B 1R6, Canada
| | - Samuel R Little
- Department of Electrical and Computer Engineering, Concordia University, 1455 de Maisonneuve Blvd. West, Montréal, Québec, H3G 1M8, Canada
- Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke Street West, Montréal, Québec, H4B 1R6, Canada
| | - Annie Fortin
- Human Health Therapeutics Research Centre, National Research Council Canada, Montréal, Québec, H4P 2R2, Canada
| | - Anna N Moraitis
- Human Health Therapeutics Research Centre, National Research Council Canada, Montréal, Québec, H4P 2R2, Canada
| | - Steve C C Shih
- Department of Electrical and Computer Engineering, Concordia University, 1455 de Maisonneuve Blvd. West, Montréal, Québec, H3G 1M8, Canada
- Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke Street West, Montréal, Québec, H4B 1R6, Canada
- Department of Biology, Concordia University, 7141 Sherbrooke Street West, Montréal, Québec, H4B 1R6, Canada
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2
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Boran Z, Fan Y, Wenshuai W, Wuyi W, Wenhan Z, Qianbin Z. Investigation of particle manipulation mechanism and size sorting strategy in a double-layered microchannel. LAB ON A CHIP 2022; 22:4556-4573. [PMID: 36321548 DOI: 10.1039/d2lc00822j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Traditionally, comprehensive laboratorial experiments on newly proposed microfluidic devices are necessary for theoretical validation, technological design, methodological calibration and optimization. Multiple parameters and characteristics, such as the flow rate, particle size, microchannel dimensions, etc., should be studied by controlled trials, which could inevitably result in extensive experiments and a heavy burden on researchers. In this work, a novel numerical model was introduced to simulate particle migration within a complicated double-layered microchannel. Using the hybrid meshing method, the proposed model achieved a significant improvement in meshing quality, and remarkably reduced the required calculation resources at the same time. The robust, efficient and resource-saving numerical model was calibrated and validated with experimental results. Based on this model, 1) the mechanism of microparticle manipulation within the microchannel was revealed; 2) the primary reason for the microparticle focusing failure was investigated; and 3) the optimal microparticle sorting strategy at different flow rates was analyzed. In experiments, the obtained optimal strategy could approach a good sorting performance with a high recovery rate and high concentration ratio in a high-throughput manner. The proposed numerical model shows great potential in mechanism investigation and functional prediction for microfluidic technologies using unconventional designs.
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Affiliation(s)
- Zhang Boran
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore
- Department of Hydraulic Engineering, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, P. R. China
| | - Yang Fan
- College of Engineering, Peking University, Beijing 100871, China
| | - Wu Wenshuai
- Research Center for Analytical Instrumentation, Institute of Cyber-Systems and Control, State Key Laboratory of Industrial Control Technology, Zhejiang University, Hangzhou 310027, China.
| | - Wan Wuyi
- Department of Hydraulic Engineering, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, P. R. China
| | - Zhao Wenhan
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore
| | - Zhao Qianbin
- Center for Health Science and Engineering, Hebei Key Laboratory of Biomaterials and Smart Theranostics, School of Health Sciences and Biomedical Engineering, Hebei University of Technology, Tianjin 300131, China.
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3
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Samlali K, Alves CL, Jezernik M, Shih SCC. Droplet digital microfluidic system for screening filamentous fungi based on enzymatic activity. MICROSYSTEMS & NANOENGINEERING 2022; 8:123. [PMID: 36438986 PMCID: PMC9681769 DOI: 10.1038/s41378-022-00456-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 07/24/2022] [Accepted: 09/13/2022] [Indexed: 06/16/2023]
Abstract
Fungal cell-wall-degrading enzymes have great utility in the agricultural and food industries. These cell-wall-degrading enzymes are known to have functions that can help defend against pathogenic organisms. The existing methods used to discover these enzymes are not well adapted to fungi culture and morphology, which prevents the proper evaluation of these enzymes. We report the first droplet-based microfluidic method capable of long-term incubation and low-voltage conditions to sort filamentous fungi inside nanoliter-sized droplets. The new method was characterized and validated in solid-phase media based on colloidal chitin such that the incubation of single spores in droplets was possible over multiple days (2-4 days) and could be sorted without droplet breakage. With long-term culture, we examined the activity of cell-wall-degrading enzymes produced by fungi during solid-state droplet fermentation using three highly sensitive fluorescein-based substrates. We also used the low-voltage droplet sorter to select clones with highly active cell-wall-degrading enzymes, such as chitinases, β-glucanases, and β-N-acetylgalactosaminidases, from a filamentous fungi droplet library that had been incubated for >4 days. The new system is portable, affordable for any laboratory, and user-friendly compared to classical droplet-based microfluidic systems. We propose that this system will be useful for the growing number of scientists interested in fungal microbiology who are seeking high-throughput methods to incubate and sort a large library of fungal cells.
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Affiliation(s)
- Kenza Samlali
- Department of Electrical and Computer Engineering, Concordia University, Montréal, QC Canada
- Centre for Applied Synthetic Biology, Concordia University, Montréal, QC Canada
| | - Chiara Leal Alves
- Department of Electrical and Computer Engineering, Concordia University, Montréal, QC Canada
- Centre for Applied Synthetic Biology, Concordia University, Montréal, QC Canada
| | - Mara Jezernik
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON Canada
| | - Steve C. C. Shih
- Department of Electrical and Computer Engineering, Concordia University, Montréal, QC Canada
- Centre for Applied Synthetic Biology, Concordia University, Montréal, QC Canada
- Department of Biology, Concordia University, Montréal, QC Canada
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4
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Kessler M, Elettro H, Heimgartner I, Madasu S, Brakke KA, Gallaire F, Amstad E. Everything in its right place: controlling the local composition of hydrogels using microfluidic traps. LAB ON A CHIP 2020; 20:4572-4581. [PMID: 33146208 DOI: 10.1039/d0lc00691b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Many natural materials display locally varying compositions that impart unique mechanical properties to them which are still unmatched by manmade counterparts. Synthetic materials often possess structures that are well-defined on the molecular level, but poorly defined on the microscale. A fundamental difference that leads to this dissimilarity between natural and synthetic materials is their processing. Many natural materials are assembled from compartmentalized reagents that are released in well-defined and spatially confined regions, resulting in locally varying compositions. By contrast, synthetic materials are typically processed in bulk. Inspired by nature, we introduce a drop-based technique that enables the design of microstructured hydrogel sheets possessing tuneable locally varying compositions. This control in the spatial composition and microstructure is achieved with a microfluidic Hele-Shaw cell that possesses traps with varying trapping strengths to selectively immobilize different types of drops. This modular platform is not limited to the fabrication of hydrogels but can be employed for any material that can be processed into drops and solidified within them. It likely opens up new possibilities for the design of structured, load-bearing hydrogels, as well as for the next generation of soft actuators and sensors.
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Affiliation(s)
- Michael Kessler
- Soft Materials Laboratory, Institute of Materials, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
| | - Hervé Elettro
- Laboratory of Fluid Mechanics and Instabilities, Institute of Mechanical Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Isabelle Heimgartner
- Soft Materials Laboratory, Institute of Materials, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
| | - Soujanya Madasu
- Soft Materials Laboratory, Institute of Materials, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
| | - Kenneth A Brakke
- Mathematics Department, Susquehanna University, Selinsgrove, PA 17870, USA
| | - François Gallaire
- Laboratory of Fluid Mechanics and Instabilities, Institute of Mechanical Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Esther Amstad
- Soft Materials Laboratory, Institute of Materials, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
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5
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Bonart H, Kahle C, Repke JU. Optimal Control of Droplets on a Solid Surface Using Distributed Contact Angles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:8894-8903. [PMID: 32628852 DOI: 10.1021/acs.langmuir.0c01242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Controlling the shape and position of moving and pinned droplets on a solid surface is an important feature often found in microfluidic applications. However, automating them, e.g., for high-throughput applications, rarely involves model-based optimal control strategies. In this work, we demonstrate the optimal control of both the shape and position of a droplet sliding on an inclined surface. This basic test case is a fundamental building block in plenty of microfluidic designs. The static contact angle between the solid surface, the surrounding gas, and the liquid droplet serves as the control variable. By using several control patches, e.g., like that performed in electrowetting, the contact angles are allowed to vary in space and time. In computer experiments, we are able to calculate mathematically optimal contact angle distributions using gradient-based optimization. The dynamics of the droplet are described by the Cahn-Hilliard-Navier-Stokes equations. We anticipate our demonstration to be the starting point for more sophisticated optimal design and control concepts.
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Affiliation(s)
- Henning Bonart
- Technische Universität Berlin, Process Dynamics and Operations Group, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Christian Kahle
- Universität Koblenz-Landau, Universitätsstraße 1, 56070 Koblenz, Germany
| | - Jens-Uwe Repke
- Technische Universität Berlin, Process Dynamics and Operations Group, Straße des 17. Juni 135, 10623 Berlin, Germany
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6
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Samlali K, Ahmadi F, Quach ABV, Soffer G, Shih SCC. One Cell, One Drop, One Click: Hybrid Microfluidics for Mammalian Single Cell Isolation. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2002400. [PMID: 32705796 DOI: 10.1002/smll.202002400] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/18/2020] [Indexed: 06/11/2023]
Abstract
Generating a stable knockout cell line is a complex process that can take several months to complete. In this work, a microfluidic method that is capable of isolating single cells in droplets, selecting successful edited clones, and expansion of these isoclones is introduced. Using a hybrid microfluidics method, droplets in channels can be individually addressed using a co-planar electrode system. In the hybrid microfluidics device, it is shown that single cells can be trapped and subsequently encapsulate them on demand into pL-sized droplets. Furthermore, droplets containing single cells are either released, kept in the traps, or merged with other droplets by the application of an electric potential to the electrodes that is actuated through an in-house user interface. This high precision control is used to successfully sort and recover single isoclones to establish monoclonal cell lines, which is demonstrated with a heterozygous NCI-H1299 lung squamous cell population resulting from loss-of-function eGFP and RAF1 gene knockout transfections.
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Affiliation(s)
- Kenza Samlali
- Department of Electrical and Computer Engineering, Concordia University, Montréal, Québec, H3G 1M8, Canada
- Centre for Applied Synthetic Biology, Concordia University, Montréal, Québec, H4B 1R6, Canada
| | - Fatemeh Ahmadi
- Department of Electrical and Computer Engineering, Concordia University, Montréal, Québec, H3G 1M8, Canada
- Centre for Applied Synthetic Biology, Concordia University, Montréal, Québec, H4B 1R6, Canada
| | - Angela B V Quach
- Centre for Applied Synthetic Biology, Concordia University, Montréal, Québec, H4B 1R6, Canada
- Department of Biology, Concordia University, Montréal, Québec, H4B 1R6, Canada
| | - Guy Soffer
- Department of Electrical and Computer Engineering, Concordia University, Montréal, Québec, H3G 1M8, Canada
- Centre for Applied Synthetic Biology, Concordia University, Montréal, Québec, H4B 1R6, Canada
| | - Steve C C Shih
- Department of Electrical and Computer Engineering, Concordia University, Montréal, Québec, H3G 1M8, Canada
- Centre for Applied Synthetic Biology, Concordia University, Montréal, Québec, H4B 1R6, Canada
- Department of Biology, Concordia University, Montréal, Québec, H4B 1R6, Canada
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7
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Payne EM, Holland-Moritz DA, Sun S, Kennedy RT. High-throughput screening by droplet microfluidics: perspective into key challenges and future prospects. LAB ON A CHIP 2020; 20:2247-2262. [PMID: 32500896 DOI: 10.1039/d0lc00347f] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
In two decades of development, impressive strides have been made for automating basic laboratory operations in droplet-based microfluidics, allowing the emergence of a new form of high-throughput screening and experimentation in nanoliter to femtoliter volumes. Despite advancements in droplet storage, manipulation, and analysis, the field has not yet been widely adapted for many high-throughput screening (HTS) applications. Broad adoption and commercial development of these techniques require robust implementation of strategies for the stable storage, chemical containment, generation of libraries, sample tracking, and chemical analysis of these small samples. We discuss these challenges for implementing droplet HTS and highlight key strategies that have begun to address these concerns. Recent advances in the field leave us optimistic about the future prospects of this rapidly developing technology.
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Affiliation(s)
- Emory M Payne
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA.
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8
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Navi M, Abbasi N, Salari A, Tsai SSH. Magnetic water-in-water droplet microfluidics: Systematic experiments and scaling mathematical analysis. BIOMICROFLUIDICS 2020; 14:024101. [PMID: 32161632 PMCID: PMC7056455 DOI: 10.1063/1.5144137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 02/23/2020] [Indexed: 05/30/2023]
Abstract
A major barrier to the clinical utilization of microfluidically generated water-in-oil droplets is the cumbersome washing steps required to remove the non-biocompatible organic oil phase from the droplets. In this paper, we report an on-chip magnetic water-in-water droplet generation and manipulation platform using a biocompatible aqueous two-phase system of a polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer (PEG-PPG-PEG) and dextran (DEX), eliminating the need for subsequent washing steps. By careful selection of a ferrofluid that shows an affinity toward the DEX phase (the dispersed phase in our microfluidic device), we generate magnetic DEX droplets in a non-magnetic continuous phase of PEG-PPG-PEG. We apply an external magnetic field to manipulate the droplets and sort them into different outlets. We also perform scaling analysis to model the droplet deflection and find that the experimental data show good agreement with the model. We expect that this type of all-biocompatible magnetic droplet microfluidic system will find utility in biomedical applications, such as long-term single cell analysis. In addition, the model can be used for designing experimental parameters to achieve a desired droplet trajectory.
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9
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Baratian D, Ruiz-Gutiérrez É, Mugele F, Ledesma-Aguilar R. Slippery when wet: mobility regimes of confined drops in electrowetting. SOFT MATTER 2019; 15:7063-7070. [PMID: 31441482 DOI: 10.1039/c9sm01107b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The motion of confined droplets in immiscible liquid-liquid systems strongly depends on the intrinsic relative wettability of the liquids on the confining solid material and on the typical speed, which can induce the formation of a lubricating layer of the continuous phase. In electrowetting, which routinely makes use of aqueous drops in ambient non-polar fluids that wet the wall material, electric stresses enter the force balance in addition to capillary and viscous forces and confinement effects. Here, we study the mobility of droplets upon electrowetting actuation in a wedge-shaped channel, and the subsequent relaxation when the electrowetting actuation is removed. We find that the droplets display two different mobility regimes: a fast regime, corresponding to gliding on a thin film of the ambient fluid, and a slow regime, where the film is replaced by direct contact between the droplet and the channel walls. Using a combination of experiments and numerical simulations, we show that the cross-over between these regimes arises from the interplay between the small-scale dynamics of the thin film of ambient fluid and the large-scale motion of the droplet. Our results shed light on the complex dynamics of droplets in non-uniform channels driven by electric actuation, and can thus help the rational design of devices based on electrowetting-driven droplet transport.
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Affiliation(s)
- Davood Baratian
- Physics of Complex Fluids, MESA+ Institute for Nanotechnology, Department of Science and Technology, University of Twente, The Netherlands
| | - Élfego Ruiz-Gutiérrez
- Smart Materials and Surfaces Laboratory, Faculty of Engineering and Environment, Northumbria University, Ellison Place, Newcastle upon Tyne NE1 8ST, UK.
| | - Frieder Mugele
- Physics of Complex Fluids, MESA+ Institute for Nanotechnology, Department of Science and Technology, University of Twente, The Netherlands
| | - Rodrigo Ledesma-Aguilar
- Smart Materials and Surfaces Laboratory, Faculty of Engineering and Environment, Northumbria University, Ellison Place, Newcastle upon Tyne NE1 8ST, UK.
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10
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Suea-Ngam A, Howes PD, Srisa-Art M, deMello AJ. Droplet microfluidics: from proof-of-concept to real-world utility? Chem Commun (Camb) 2019; 55:9895-9903. [PMID: 31334541 DOI: 10.1039/c9cc04750f] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Droplet microfluidics constitutes a diverse and practical tool set that enables chemical and biological experiments to be performed at high speed and with enhanced efficiency when compared to conventional instrumentation. Indeed, in recent years, droplet-based microfluidic tools have been used to excellent effect in a range of applications, including materials synthesis, single cell analysis, RNA sequencing, small molecule screening, in vitro diagnostics and tissue engineering. Our 2011 Chemical Communications Highlight Article [Chem. Commun., 2011, 47, 1936-1942] reviewed some of the most important technological developments and applications of droplet microfluidics, and identified key challenges that needed to be addressed in the short term. In the current contribution, we consider the intervening eight years, and assess the contributions that droplet-based microfluidics has made to experimental science in its broadest sense.
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Affiliation(s)
- Akkapol Suea-Ngam
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1, 8093 Zürich, Switzerland.
| | - Philip D Howes
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1, 8093 Zürich, Switzerland.
| | - Monpichar Srisa-Art
- Electrochemistry and Optical Spectroscopy Center of Excellence, Department of Chemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok, 10330, Thailand
| | - Andrew J deMello
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1, 8093 Zürich, Switzerland.
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11
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Zhang J, Hassan MR, Rallabandi B, Wang C. Migration of ferrofluid droplets in shear flow under a uniform magnetic field. SOFT MATTER 2019; 15:2439-2446. [PMID: 30801084 DOI: 10.1039/c8sm02522c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Manipulation of droplets based on physical properties (e.g., size, interfacial tension, electrical, and mechanical properties) is a critical step in droplet microfluidics. Manipulations based on magnetic fields have several benefits compared to other active methods. While traditional magnetic manipulations require spatially inhomogeneous fields to apply forces, the fast spatial decay of the magnetic field strength from the source makes these techniques difficult to scale up. In this work, we report the observation of lateral migration of ferrofluid (or magnetic) droplets under the combined action of a uniform magnetic field and a pressure-driven flow in a microchannel. While the uniform magnetic field exerts negligible net force on the droplet, the Maxwell stresses deform the droplet to achieve elongated shapes and modulate the orientation relative to the fluid flow. Hydrodynamic interactions between the droplets and the channel walls result in a directional lateral migration. We experimentally study the effects of field strength and direction, and interfacial tension, and use analytical and numerical modeling to understand the lateral migration mechanism.
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Affiliation(s)
- Jie Zhang
- Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, 400 W. 13th St., Rolla, Missouri 65409, USA.
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12
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Ahmadi F, Samlali K, Vo PQN, Shih SCC. An integrated droplet-digital microfluidic system for on-demand droplet creation, mixing, incubation, and sorting. LAB ON A CHIP 2019; 19:524-535. [PMID: 30633267 DOI: 10.1039/c8lc01170b] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Droplet microfluidics is a technique that has the ability to compartmentalize reactions in sub nano- (or pico-) liter volumes that can potentially enable millions of distinct biological assays to be performed on individual cells. In a typical droplet microfluidic system, droplets are manipulated by pressure-based flows. This has limited the fluidic operations that can be performed in these devices. Digital microfluidics is an alternative microfluidic paradigm with precise control and manipulation over individual droplets. Here, we implement an integrated droplet-digital microfluidic (which we call 'ID2M') system in which common fluidic operations (i.e. droplet generation, cell encapsulation, droplet merging and mixing, droplet trapping and incubation, and droplet sorting) can be performed. With the addition of electrodes, we have been able to create droplets on-demand, tune their volumes on-demand, and merge and mix several droplets to produce a dilution series. Moreover, this device can trap and incubate droplets for 24 h that can consequently be sorted and analyzed in multiple n-ary channels (as opposed to typical binary channels). The ID2M platform has been validated as a robust on-demand screening system by sorting fluorescein droplets of different concentration with an efficiency of ∼96%. The utility of the new system is further demonstrated by culturing and sorting tolerant yeast mutants and wild-type yeast cells in ionic liquid based on their growth profiles. This new platform for both droplet and digital microfluidics has the potential to be used for screening different conditions on-chip and for applications like directed evolution.
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Affiliation(s)
- Fatemeh Ahmadi
- Department of Electrical and Computer Engineering, Concordia University, Montréal, Québec, Canada.
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13
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Gao ZF, Liu R, Wang J, Dai J, Huang WH, Liu M, Wang S, Xia F, Jiang L. Controlling Droplet Motion on an Organogel Surface by Tuning the Chain Length of DNA and Its Biosensing Application. Chem 2018. [DOI: 10.1016/j.chempr.2018.09.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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14
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Luo X, Huang X, Yan H, Yang D, Wang J, He L. Breakup modes and criterion of droplet with surfactant under direct current electric field. Chem Eng Res Des 2018. [DOI: 10.1016/j.cherd.2018.02.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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15
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Sesen M, Alan T, Neild A. Droplet control technologies for microfluidic high throughput screening (μHTS). LAB ON A CHIP 2017. [PMID: 28631799 DOI: 10.1039/c7lc00005g] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The transition from micro well plate and robotics based high throughput screening (HTS) to chip based screening has already started. This transition promises reduced droplet volumes thereby decreasing the amount of fluids used in these studies. Moreover, it significantly boosts throughput allowing screening to keep pace with the overwhelming number of molecular targets being discovered. In this review, we analyse state-of-the-art droplet control technologies that exhibit potential to be used in this new generation of screening devices. Since these systems are enclosed and usually planar, even some of the straightforward methods used in traditional HTS such as pipetting and reading can prove challenging to replicate in microfluidic high throughput screening (μHTS). We critically review the technologies developed for this purpose in depth, describing the underlying physics and discussing the future outlooks.
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Affiliation(s)
- Muhsincan Sesen
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia.
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16
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Abstract
Droplet microfluidics generates and manipulates discrete droplets through immiscible multiphase flows inside microchannels. Due to its remarkable advantages, droplet microfluidics bears significant value in an extremely wide range of area. In this review, we provide a comprehensive and in-depth insight into droplet microfluidics, covering fundamental research from microfluidic chip fabrication and droplet generation to the applications of droplets in bio(chemical) analysis and materials generation. The purpose of this review is to convey the fundamentals of droplet microfluidics, a critical analysis on its current status and challenges, and opinions on its future development. We believe this review will promote communications among biology, chemistry, physics, and materials science.
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Affiliation(s)
- Luoran Shang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, China
| | - Yao Cheng
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, China
| | - Yuanjin Zhao
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, China
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Xi HD, Zheng H, Guo W, Gañán-Calvo AM, Ai Y, Tsao CW, Zhou J, Li W, Huang Y, Nguyen NT, Tan SH. Active droplet sorting in microfluidics: a review. LAB ON A CHIP 2017; 17:751-771. [PMID: 28197601 DOI: 10.1039/c6lc01435f] [Citation(s) in RCA: 174] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The ability to manipulate and sort droplets is a fundamental issue in droplet-based microfluidics. Various lab-on-a-chip applications can only be realized if droplets are systematically categorized and sorted. These micron-sized droplets act as ideal reactors which compartmentalize different biological and chemical reagents. Array processing of these droplets hinges on the competence of the sorting and integration into the fluidic system. Recent technological advances only allow droplets to be actively sorted at the rate of kilohertz or less. In this review, we present state-of-the-art technologies which are implemented to efficiently sort droplets. We classify the concepts according to the type of energy implemented into the system. We also discuss various key issues and provide insights into various systems.
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Affiliation(s)
- Heng-Dong Xi
- School of Aeronautics, Northwestern Polytechnical University, 127 West Youyi Rd., Xi'an, Shaanxi, China
| | - Hao Zheng
- School of Aeronautics, Northwestern Polytechnical University, 127 West Youyi Rd., Xi'an, Shaanxi, China
| | - Wei Guo
- School of Aeronautics, Northwestern Polytechnical University, 127 West Youyi Rd., Xi'an, Shaanxi, China and Queensland Micro- and Nanotechnology Centre, Griffith University, 170 Kessels Road, Brisbane, QLD 4111, Australia.
| | - Alfonso M Gañán-Calvo
- Depto. de Ingeniería Aeroespacial y Mecánica de Fluidos, Universidad de Sevilla, E-41092 Sevilla, Spain
| | - Ye Ai
- Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore
| | - Chia-Wen Tsao
- Department of Mechanical Engineering, National Central University, No. 300, Zhongda Rd, Taoyuan, Taiwan
| | - Jun Zhou
- School of Information and Communication Technology, Griffith University, Nathan, QLD 4111, Australia
| | - Weihua Li
- School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Yanyi Huang
- Biodynamic Optical Imaging Center, Peking University, Beijing 100871, China
| | - Nam-Trung Nguyen
- Queensland Micro- and Nanotechnology Centre, Griffith University, 170 Kessels Road, Brisbane, QLD 4111, Australia.
| | - Say Hwa Tan
- Queensland Micro- and Nanotechnology Centre, Griffith University, 170 Kessels Road, Brisbane, QLD 4111, Australia.
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18
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Wildeman S, Sun C. Electric field makes Leidenfrost droplets take a leap. SOFT MATTER 2016; 12:9622-9632. [PMID: 27858052 DOI: 10.1039/c6sm01506a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Leidenfrost droplets, i.e. droplets whose mobility is ensured by a thin vapor film between the droplet and a hot plate, are exposed to an external electric field. We find that in a strong vertical electric field the droplet can start to bounce progressively higher, defying gravitational attraction. From the droplet's trajectory we infer the temporal evolution of the amount of charge on the droplet. This reveals that the charge starts high and then decreases in steps as the droplet slowly evaporates. After each discharge event the charge is in a fixed proportion to the droplet's surface area. We show that this behavior can be accurately modeled by treating the droplet as a conducting sphere that occasionally makes electrical contact with the hot plate, at intervals dictated by an electro-capillary instability in the vapor film. An analysis of the kinetic and potential energies of the bouncing droplet reveals that, while the overall motion is damped, the droplet occasionally experiences a sudden boost, keeping its energy close to the value for which the free fall trajectory and droplet oscillation are in sync. This helps the droplet to escape from the hot surface when finally the electrical surface forces overtake gravity.
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Affiliation(s)
- Sander Wildeman
- Physics of Fluids Group, University of Twente, 7500, AE Enschede, The Netherlands.
| | - Chao Sun
- Center for Combustion Energy and Department of Thermal Engineering, Tsinghua University, 100084 Beijing, China and Physics of Fluids Group, University of Twente, 7500, AE Enschede, The Netherlands.
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19
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Bera B, Duits MHG, Cohen Stuart MA, van den Ende D, Mugele F. Surfactant induced autophobing. SOFT MATTER 2016; 12:4562-4571. [PMID: 27102975 DOI: 10.1039/c6sm00128a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Surfactant adsorption in a three-phase system and its influence on wetting properties are relevant in various applications. Here, we report a hitherto not observed phenomenon, namely the retraction of an aqueous drop on hydrophilic solid substrates (which we refer to as 'autophobing') in ambient oil containing water-insoluble fatty acids, caused by the deposition of these fatty acids from the ambient oil onto the solid substrate. AFM measurements confirm that the surfactant is deposited on the solid by the moving contact line. This leads to a more hydrophobic substrate, the retraction of the contact line and a concomitant increase in the contact angle. The deposition process is enabled by the formation of a reaction product between deprotonated fatty acids and Ca(2+) ions at the oil/water interface. We investigate how the transition to a new equilibrium depends on the concentrations of the fatty acids, the aqueous solute, the chain lengths of the fatty acid, and the types of alkane solvent and silica or mica substrates. This phenomenon is observed on both substrates and for all explored combinations of fatty acids and solvents and thus appears to be generic. In order to capture the evolution of the contact angle, we develop a theoretical model in which the rate of adsorption at the oil-water interface governs the overall kinetics of autophobing, and transfer to the solid is determined by a mass flux balance (similar to a Langmuir Blodgett transfer).
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Affiliation(s)
- B Bera
- Physics of Complex Fluids (PCF) Group, MESA + Institute of Technology, University of Twente, Enschede, The Netherlands.
| | - M H G Duits
- Physics of Complex Fluids (PCF) Group, MESA + Institute of Technology, University of Twente, Enschede, The Netherlands.
| | - M A Cohen Stuart
- Physics of Complex Fluids (PCF) Group, MESA + Institute of Technology, University of Twente, Enschede, The Netherlands.
| | - D van den Ende
- Physics of Complex Fluids (PCF) Group, MESA + Institute of Technology, University of Twente, Enschede, The Netherlands.
| | - F Mugele
- Physics of Complex Fluids (PCF) Group, MESA + Institute of Technology, University of Twente, Enschede, The Netherlands.
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20
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Fradet E, Bayer C, Hollfelder F, Baroud CN. Measuring Fast and Slow Enzyme Kinetics in Stationary Droplets. Anal Chem 2015; 87:11915-22. [DOI: 10.1021/acs.analchem.5b03567] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Etienne Fradet
- Laboratoire
d’Hydrodynamique (LadHyX) and Department of Mechanics, Ecole Polytechnique, CNRS, 91128, Palaiseau, France
| | - Christopher Bayer
- Department
of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, United Kingdom CB2 1GA
| | - Florian Hollfelder
- Department
of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, United Kingdom CB2 1GA
| | - Charles N. Baroud
- Laboratoire
d’Hydrodynamique (LadHyX) and Department of Mechanics, Ecole Polytechnique, CNRS, 91128, Palaiseau, France
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21
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22
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Pit AM, de Ruiter R, Kumar A, Wijnperlé D, Duits MHG, Mugele F. High-throughput sorting of drops in microfluidic chips using electric capacitance. BIOMICROFLUIDICS 2015; 9:044116. [PMID: 26339316 PMCID: PMC4537480 DOI: 10.1063/1.4928452] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 07/30/2015] [Indexed: 05/11/2023]
Abstract
We analyze a recently introduced approach for the sorting of aqueous drops with biological content immersed in oil, using a microfluidic chip that combines the functionality of electrowetting with the high throughput of two-phase flow microfluidics. In this electrostatic sorter, three co-planar electrodes covered by a thin dielectric layer are placed directly below the fluidic channel. Switching the potential of the central electrode creates an electrical guide that leads the drop to the desired outlet. The generated force, which deflects the drop, can be tuned via the voltage. The working principle is based on a contrast in conductivity between the drop and the continuous phase, which ensures successful operation even for drops of highly conductive biological media like phosphate buffered saline. Moreover, since the electric field does not penetrate the drop, its content is protected from electrical currents and Joule heating. A simple capacitive model allows quantitative prediction of the electrostatic forces exerted on drops. The maximum achievable sorting rate is determined by a competition between electrostatic and hydrodynamic forces. Sorting speeds up to 1200 per second are demonstrated for conductive drops of 160 pl in low viscosity oil.
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Affiliation(s)
- Arjen M Pit
- Physics of Complex Fluids Group, MESA+ Institute, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Riëlle de Ruiter
- Physics of Complex Fluids Group, MESA+ Institute, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Anand Kumar
- Physics of Complex Fluids Group, MESA+ Institute, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Daniel Wijnperlé
- Physics of Complex Fluids Group, MESA+ Institute, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Michèl H G Duits
- Physics of Complex Fluids Group, MESA+ Institute, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Frieder Mugele
- Physics of Complex Fluids Group, MESA+ Institute, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
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Cavalli A, Musterd M, Mugele F. Numerical investigation of dynamic effects for sliding drops on wetting defects. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:023013. [PMID: 25768603 DOI: 10.1103/physreve.91.023013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Indexed: 06/04/2023]
Abstract
The ability to trap or deflect sliding drops is of great interest in microfluidics, as it has several technological applications, ranging from self-cleaning and fog harvesting surfaces to laboratory-on-a-chip devices. We present a three-dimensional numerical model that describes sliding droplets interacting with wetting defects of variable strength and size. This approach provides relevant insight if compared to simplified analytic models, as it allows us to assess the relevance of the internal degrees of freedom of the droplet. We observe that the deformation of the drop enhances the effective strength and range of the defect, and we quantify this effect by comparison to a point-mass model. We also analyze the role of the steepness and strength of the defect on the drop motion, observing that small, strong defects are more effective at trapping than large, shallow traps of same excess surface energy. Finally, our results show quantitative agreement with previously reported electrowetting experiments, suggesting a universal behavior in droplet trapping that does not depend strongly on the nature of the defect.
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Affiliation(s)
- Andrea Cavalli
- Physics of Complex Fluids and MESA+ Institute for Nanotechnology, University of Twente, 7522 NB Enschede, The Netherlands
| | - Michiel Musterd
- Product and Process Engineering, TNW-PPE/TP, Delft University of Technology, 2628 CN Delft, The Netherlands
| | - Frieder Mugele
- Physics of Complex Fluids and MESA+ Institute for Nanotechnology, University of Twente, 7522 NB Enschede, The Netherlands
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24
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Abstract
Controlling the motion of drops on solid surfaces is crucial in many natural phenomena and technological processes including the collection and removal of rain drops, cleaning technology and heat exchangers. Topographic and chemical heterogeneities on solid surfaces give rise to pinning forces that can capture and steer drops in desired directions. Here we determine general physical conditions required for capturing sliding drops on an inclined plane that is equipped with electrically tunable wetting defects. By mapping the drop dynamics on the one-dimensional motion of a point mass, we demonstrate that the trapping process is controlled by two dimensionless parameters, the trapping strength measured in units of the driving force and the ratio between a viscous and an inertial time scale. Complementary experiments involving superhydrophobic surfaces with wetting defects demonstrate the general applicability of the concept. Moreover, we show that electrically tunable defects can be used to guide sliding drops along actively switchable tracks-with potential applications in microfluidics.
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