1
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Zhuang S, Semenec L, Nagy SS, Cain AK, Inglis DW. High-precision screening and sorting of double emulsion droplets. Cytometry A 2024. [PMID: 38634684 DOI: 10.1002/cyto.a.24842] [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: 12/14/2023] [Revised: 03/25/2024] [Accepted: 04/04/2024] [Indexed: 04/19/2024]
Abstract
Mounting evidence suggests that cell populations are extremely heterogeneous, with individual cells fulfilling different roles within the population. Flow cytometry (FC) is a high-throughput tool for single-cell analysis that works at high optical resolution. Sub-populations with unique properties can be screened, isolated and sorted through fluorescence-activated cell sorting (FACS), using intracellular fluorescent products or surface-tagged fluorescent products of interest. However, traditional FC and FACS methods cannot identify or isolate cells that secrete extracellular products of interest. Double emulsion (DE) droplets are an innovative approach to retaining these extracellular products so cells producing them can be identified and isolated with FC and FACS. The water-in-oil-in-water structure makes DE droplets compatible with the sheath flow of flow cytometry. Single cells can be encapsulated with other reagents into DEs, which act as pico-reactors. These droplets allow biological activities to take place while allowing for cell cultivation monitoring, rare mutant identification, and cellular events characterization. However, using DEs in FACS presents technical challenges, including rupture of DEs, poor accuracy and low sorting efficiency. This study presents high-performance sorting using fluorescent beads (as simulants for cells). This study aims to guide researchers in the use of DE-based flow cytometry, offering insights into how to resolve the technical difficulties associated with DE-based screening and sorting using FC.
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Affiliation(s)
- Siyuan Zhuang
- School of Engineering, Macquarie University, Sydney, New South Wales, Australia
| | - Lucie Semenec
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Stephanie S Nagy
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Amy K Cain
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - David W Inglis
- School of Engineering, Macquarie University, Sydney, New South Wales, Australia
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2
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Review of the role of surfactant dynamics in drop microfluidics. Adv Colloid Interface Sci 2023; 312:102844. [PMID: 36708604 DOI: 10.1016/j.cis.2023.102844] [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: 11/15/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/20/2023]
Abstract
Surfactants are employed in microfluidic systems not just for drop stabilisation, but also to study local phenomena in industrial processes. On the scale of a single drop, these include foaming, emulsification and stability of foams and emulsions using statistically significant ensembles of bubbles or drops respectively. In addition, surfactants are often a part of a formulation in microfluidic drop reactors. In all these applications, surfactant dynamics play a crucial role and need to be accounted for. In this review, the effect of surfactant dynamics is considered on the level of standard microfluidic operations: drop formation, movement in channels and coalescence, but also on a more general level, considering the mechanisms controlling surfactant adsorption on time- and length-scales characteristic of microfluidics. Some examples of relevant calculations are provided. The advantages and challenges of the use of microfluidics to measure dynamic interfacial tension at short time-scales are discussed.
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3
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Khariton M, McClune CJ, Brower KK, Klemm S, Sattely ES, Fordyce PM, Wang B. Alleviating Cell Lysate-Induced Inhibition to Enable RT-PCR from Single Cells in Picoliter-Volume Double Emulsion Droplets. Anal Chem 2023; 95:935-945. [PMID: 36598332 DOI: 10.1021/acs.analchem.2c03475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Microfluidic droplet assays enable single-cell polymerase chain reaction (PCR) and sequencing analyses at unprecedented scales, with most methods encapsulating cells within nanoliter-sized single emulsion droplets (water-in-oil). Encapsulating cells within picoliter double emulsion (DE) (water-in-oil-in-water) allows sorting droplets with commercially available fluorescence-activated cell sorter (FACS) machines, making it possible to isolate single cells based on phenotypes of interest for downstream analyses. However, sorting DE droplets with standard cytometers requires small droplets that can pass FACS nozzles. This poses challenges for molecular biology, as prior reports suggest that reverse transcription (RT) and PCR amplification cannot proceed efficiently at volumes below 1 nL due to cell lysate-induced inhibition. To overcome this limitation, we used a plate-based RT-PCR assay designed to mimic reactions in picoliter droplets to systematically quantify and ameliorate the inhibition. We find that RT-PCR is blocked by lysate-induced cleavage of nucleic acid probes and primers, which can be efficiently alleviated through heat lysis. We further show that the magnitude of inhibition depends on the cell type, but that RT-PCR can proceed in low-picoscale reaction volumes for most mouse and human cell lines tested. Finally, we demonstrate one-step RT-PCR from single cells in 20 pL DE droplets with fluorescence quantifiable via FACS. These results open up new avenues for improving picoscale droplet RT-PCR reactions and expanding microfluidic droplet-based single-cell analysis technologies.
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Affiliation(s)
- Margarita Khariton
- Department of Bioengineering, Stanford University, Stanford, California94305, United States
| | - Conor J McClune
- Department of Chemical Engineering, Stanford University, Stanford, California94305, United States.,Howard Hughes Medical Institute, Stanford University, Stanford, California94305, United States
| | - Kara K Brower
- Department of Bioengineering, Stanford University, Stanford, California94305, United States
| | - Sandy Klemm
- Department of Genetics, Stanford University, Stanford, California94305, United States
| | - Elizabeth S Sattely
- Department of Chemical Engineering, Stanford University, Stanford, California94305, United States.,Howard Hughes Medical Institute, Stanford University, Stanford, California94305, United States
| | - Polly M Fordyce
- Department of Bioengineering, Stanford University, Stanford, California94305, United States.,Department of Genetics, Stanford University, Stanford, California94305, United States.,ChEM-H Institute, Stanford University, Stanford, California94305, United States.,Chan Zuckerberg Biohub, San Francisco, California94110, United States
| | - Bo Wang
- Department of Bioengineering, Stanford University, Stanford, California94305, United States
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4
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Liu Y, Ji M, Zhang Y, Qiao X, Yu N, Ding C, Yang L, Feng R, Chou X, Geng W. A Novel Detachable, Reusable, and Versatile Acoustic Tweezer Manipulation Platform for Biochemical Analysis and Detection Systems. BIOSENSORS 2022; 12:1179. [PMID: 36551146 PMCID: PMC9775593 DOI: 10.3390/bios12121179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 11/24/2022] [Accepted: 12/15/2022] [Indexed: 06/17/2023]
Abstract
Multifunctional, integrated, and reusable operating platforms are highly sought after in biochemical analysis and detection systems. In this study, we demonstrated a novel detachable, reusable acoustic tweezer manipulation platform that is flexible and versatile. The free interchangeability of different detachable microchannel devices on the acoustic tweezer platform was achieved by adding a waveguide layer (glass) and a coupling layer (polydimethylsiloxane (PDMS) polymer film). We designed and demonstrated the detachable multifunctional acoustic tweezer platform with three cell manipulation capabilities. In Demo I, the detachable acoustic tweezer platform is demonstrated to have the capability for parallel processing and enrichment of the sample. In Demo II, the detachable acoustic tweezer platform with capability for precise cell alignment is demonstrated. In Demo III, it was demonstrated that the detachable acoustic tweezer platform has the capability for the separation and purification of cells. Through experiments, our acoustic tweezer platform has good acoustic retention ability, reusability, and stability. More capabilities can be expanded in the future. It provides a simple, economical, and multifunctional reusable operating platform solution for biochemical analysis and detection systems.
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Affiliation(s)
- Yukai Liu
- Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, China
| | - Miaomiao Ji
- Key Laboratory of Instrumentation Science &Dynamic Measurement, North University of China, Taiyuan 030051, China
| | - Yichi Zhang
- Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, China
| | - Xiaojun Qiao
- Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, China
| | - Nanxin Yu
- Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, China
| | - Chenxi Ding
- Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, China
| | - Lingxiao Yang
- Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, China
| | - Rui Feng
- Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, China
| | - Xiujian Chou
- Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, China
| | - Wenping Geng
- Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, China
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5
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Calhoun SGK, Brower KK, Suja VC, Kim G, Wang N, McCully AL, Kusumaatmaja H, Fuller GG, Fordyce PM. Systematic characterization of effect of flow rates and buffer compositions on double emulsion droplet volumes and stability. LAB ON A CHIP 2022; 22:2315-2330. [PMID: 35593127 PMCID: PMC9195911 DOI: 10.1039/d2lc00229a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/03/2022] [Indexed: 06/15/2023]
Abstract
Double emulsion droplets (DEs) are water/oil/water droplets that can be sorted via fluorescence-activated cell sorting (FACS), allowing for new opportunities in high-throughput cellular analysis, enzymatic screening, and synthetic biology. These applications require stable, uniform droplets with predictable microreactor volumes. However, predicting DE droplet size, shell thickness, and stability as a function of flow rate has remained challenging for monodisperse single core droplets and those containing biologically-relevant buffers, which influence bulk and interfacial properties. As a result, developing novel DE-based bioassays has typically required extensive initial optimization of flow rates to find conditions that produce stable droplets of the desired size and shell thickness. To address this challenge, we conducted systematic size parameterization quantifying how differences in flow rates and buffer properties (viscosity and interfacial tension at water/oil interfaces) alter droplet size and stability, across 6 inner aqueous buffers used across applications such as cellular lysis, microbial growth, and drug delivery, quantifying the size and shell thickness of >22 000 droplets overall. We restricted our study to stable single core droplets generated in a 2-step dripping-dripping formation regime in a straightforward PDMS device. Using data from 138 unique conditions (flow rates and buffer composition), we also demonstrated that a recent physically-derived size law of Wang et al. can accurately predict double emulsion shell thickness for >95% of observations. Finally, we validated the utility of this size law by using it to accurately predict droplet sizes for a novel bioassay that requires encapsulating growth media for bacteria in droplets. This work has the potential to enable new screening-based biological applications by simplifying novel DE bioassay development.
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Affiliation(s)
- Suzanne G K Calhoun
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Kara K Brower
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.
- ChEM-H Institute, Stanford University, Stanford, CA 94305, USA
| | - Vineeth Chandran Suja
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
- School of Engineering and Applied Sciences, Harvard University, MA - 01234, USA
| | - Gaeun Kim
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.
| | - Ningning Wang
- School of Energy & Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Alexandra L McCully
- Department of Civil & Environmental Engineering, Stanford University, Stanford, CA 94305, USA
| | | | - Gerald G Fuller
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Polly M Fordyce
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.
- ChEM-H Institute, Stanford University, Stanford, CA 94305, USA
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
- Chan Zuckerberg BioHub, San Francisco, CA 94158, USA
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6
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Cowell TW, Dobria A, Han HS. Simplified, Shear Induced Generation of Double Emulsions for Robust Compartmentalization during Single Genome Analysis. ACS APPLIED MATERIALS & INTERFACES 2022; 14:20528-20537. [PMID: 35502700 DOI: 10.1021/acsami.1c22692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Drop microfluidics has driven innovations for high throughput, low input analysis techniques such as single-cell RNA-seq. However, the instability of single emulsion (SE) drops occasionally causes significant merging during drop processing, limiting most applications to single-step reactions in drops. Here, we show that double emulsion (DE) drops address this critical limitation and completely prevent drop contents from mixing. DEs show excellent stability during thermal cycling. More importantly, DEs undergo rupture into the continuous phase instead of merging, preventing content mixing and eliminating unstable drops from the downstream analysis. Due to the lack of drop merging, the monodispersity of drops is maintained throughout a workflow, enabling the deterministic manipulation of drops downstream. We also developed a simple, one-layer DE drop maker compatible with simple surface treatment using a plasma cleaner. The device allows for the robust production of single-core DEs at a wide range of flow rates and better control over the shell thickness, both of which have been significant limitations of conventional two-layer devices. This approach makes the fabrication of DE devices much more accessible, facilitating its broader adoption. Finally, we show that DE droplets eliminate content mixing and maintain compartmentalization of single virus genomes during PCR-based amplification and barcoding, while SEs mixed contents due to merging. With their resistance to content mixing, DE drops have key advantages for multistep reactions in drops, which is limited in SEs due to merging and content mixing.
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Affiliation(s)
- Thomas W Cowell
- Department of Chemistry, University of Illinois at Urbana-Champaign, 505 South Mathews Ave., Urbana, Illinois 61801, United States
| | - Andrew Dobria
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Ave., Urbana, Illinois 61801, United States
| | - Hee-Sun Han
- Department of Chemistry, University of Illinois at Urbana-Champaign, 505 South Mathews Ave., Urbana, Illinois 61801, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 W Gregory Dr., Urbana, Illinois 61801, United States
- Cancer Center at Illinois, University of Illinois at Urbana-Champaign, 405 North Mathews Ave., Urbana, Illinois 61801, United States
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, 600 S Mathews Ave., Urbana, Illinois 61801, United States
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7
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Yang Z, Ma X, Wang S, Liu D. Generation and Evolution of Double Emulsions in a Circular Microchannel. Chem Eng Sci 2022. [DOI: 10.1016/j.ces.2022.117683] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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8
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A novel microfluidic device for double emulsion formation: The effects of design parameters on droplet production performance. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2021.128059] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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9
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Stucki A, Vallapurackal J, Ward TR, Dittrich PS. Droplet Microfluidics and Directed Evolution of Enzymes: An Intertwined Journey. Angew Chem Int Ed Engl 2021; 60:24368-24387. [PMID: 33539653 PMCID: PMC8596820 DOI: 10.1002/anie.202016154] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Indexed: 12/12/2022]
Abstract
Evolution is essential to the generation of complexity and ultimately life. It relies on the propagation of the properties, traits, and characteristics that allow an organism to survive in a challenging environment. It is evolution that shaped our world over about four billion years by slow and iterative adaptation. While natural evolution based on selection is slow and gradual, directed evolution allows the fast and streamlined optimization of a phenotype under selective conditions. The potential of directed evolution for the discovery and optimization of enzymes is mostly limited by the throughput of the tools and methods available for screening. Over the past twenty years, versatile tools based on droplet microfluidics have been developed to address the need for higher throughput. In this Review, we provide a chronological overview of the intertwined development of microfluidics droplet-based compartmentalization methods and in vivo directed evolution of enzymes.
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Affiliation(s)
- Ariane Stucki
- Department of Biosystems Science and EngineeringETH ZurichMattenstrasse 26CH-4058BaselSwitzerland
- National Competence Center in Research (NCCR)Molecular Systems EngineeringBaselSwitzerland
| | - Jaicy Vallapurackal
- Department of ChemistryUniversity of BaselMattenstrasse 24aCH-4058BaselSwitzerland
- National Competence Center in Research (NCCR)Molecular Systems EngineeringBaselSwitzerland
| | - Thomas R. Ward
- Department of ChemistryUniversity of BaselMattenstrasse 24aCH-4058BaselSwitzerland
- National Competence Center in Research (NCCR)Molecular Systems EngineeringBaselSwitzerland
| | - Petra S. Dittrich
- Department of Biosystems Science and EngineeringETH ZurichMattenstrasse 26CH-4058BaselSwitzerland
- National Competence Center in Research (NCCR)Molecular Systems EngineeringBaselSwitzerland
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10
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Stucki A, Jusková P, Nuti N, Schmitt S, Dittrich PS. Synchronized Reagent Delivery in Double Emulsions for Triggering Chemical Reactions and Gene Expression. SMALL METHODS 2021; 5:e2100331. [PMID: 34927870 DOI: 10.1002/smtd.202100331] [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: 03/25/2021] [Revised: 05/21/2021] [Indexed: 06/14/2023]
Abstract
Microfluidic methods for the formation of single and double emulsion (DE) droplets allow for the encapsulation and isolation of reactants inside nanoliter compartments. Such methods have greatly enhanced the toolbox for high-throughput screening for cell or enzyme engineering and drug discovery. However, remaining challenges in the supply of reagents into these enclosed compartments limit the applicability of droplet microfluidics. Here, a strategy is introduced for on-demand delivery of reactants in DEs. Lipid vesicles are used as reactant carriers, which are co-encapsulated in double emulsions and release their cargo upon addition of an external trigger, here the anionic surfactant sodium dodecyl sulfate (SDS). The reagent present inside the lipid vesicles stays isolated from the remaining content of the DE vessel until SDS enters the DE lumen and solubilizes the vesicles' lipid bilayer. The versatility of the method is demonstrated with two critical applications chosen as representative assays for high-throughput screening: the induction of gene expression in bacteria and the initiation of an enzymatic reaction. This method not only allows for the release of the lipid vesicle content inside DEs to be synchronized for all DEs but also for the release to be triggered at any desired time.
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Affiliation(s)
- Ariane Stucki
- Department of Biosystems Science and Engineering, Bioanalytics Group, ETH Zürich, Mattenstrasse 26, Basel, CH-4058, Switzerland
- NCCR Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, Basel, CH-4058, Switzerland
| | - Petra Jusková
- Department of Biosystems Science and Engineering, Bioanalytics Group, ETH Zürich, Mattenstrasse 26, Basel, CH-4058, Switzerland
| | - Nicola Nuti
- Department of Biosystems Science and Engineering, Bioanalytics Group, ETH Zürich, Mattenstrasse 26, Basel, CH-4058, Switzerland
| | - Steven Schmitt
- Department of Biosystems Science and Engineering, Bioprocess Laboratory, ETH Zürich, Mattenstrasse 26, Basel, CH-4058, Switzerland
| | - Petra S Dittrich
- Department of Biosystems Science and Engineering, Bioanalytics Group, ETH Zürich, Mattenstrasse 26, Basel, CH-4058, Switzerland
- NCCR Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, Basel, CH-4058, Switzerland
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11
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Liu H, Piper JA, Li M. Rapid, Simple, and Inexpensive Spatial Patterning of Wettability in Microfluidic Devices for Double Emulsion Generation. Anal Chem 2021; 93:10955-10965. [PMID: 34323465 DOI: 10.1021/acs.analchem.1c01861] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Water-in-oil-in-water (w/o/w) double emulsion (DE) encapsulation has been widely used as a promising platform technology for various applications in the fields of food, cosmetics, pharmacy, chemical engineering, materials science, and synthetic biology. Unfortunately, DEs formed by conventional emulsion generation approaches in most cases are highly polydisperse, making them less desirable for quantitative assays, controlled biomaterial synthesis, and entrapped ingredient release. Microfluidic devices can generate monodisperse DEs with controllable size, morphology, and production rate, but these generally require multistep fabrication processes and use of different solvents or bulky external instrumentation to pattern channel wettability. To overcome these limitations, we propose a rapid, simple, and inexpensive method to spatially pattern wettability in microfluidic devices for the continuous generation of monodisperse DEs. This is achieved by applying corona-plasma treatment to a select zone of the microchannel surface aided by a custom-designed corona resistance microchannel to strictly confine the plasma-treatment zone in a single polydimethylsiloxane (PDMS) microfluidic device. The properties of PDMS channel surfaces and key microchannel regions for DE generation are characterized under different levels of treatment. The size, shell thickness, and number of inner cores of generated DEs are shown to be highly controllable by tuning the phase flow rate ratios. Using DEs as templates, we successfully achieve a one-step generation and collection of gelatin microgels. Additionally, we demonstrate the biological capability of generated DEs by flow cytometric screening of the encapsulation and growth of yeast cells within DEs. We expect that the proposed approach will be widely used to create microfluidic devices with more complex wettability patterns.
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Affiliation(s)
- Hangrui Liu
- ARC Centre of Excellence for Nanoscale BioPhotonics, Macquarie University, Balaclava Road, North Ryde, New South Wales 2109, Australia.,Department of Physics and Astronomy, Macquarie University, Balaclava Road, North Ryde, New South Wales 2109, Australia
| | - James A Piper
- ARC Centre of Excellence for Nanoscale BioPhotonics, Macquarie University, Balaclava Road, North Ryde, New South Wales 2109, Australia.,Department of Physics and Astronomy, Macquarie University, Balaclava Road, North Ryde, New South Wales 2109, Australia
| | - Ming Li
- School of Engineering, Macquarie University, Balaclava Road, North Ryde, New South Wales 2109, Australia.,Biomolecular Discovery Research Centre, Macquarie University, Balaclava Road, North Ryde, New South Wales 2109, Australia
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12
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Stucki A, Vallapurackal J, Ward TR, Dittrich PS. Droplet Microfluidics and Directed Evolution of Enzymes: An Intertwined Journey. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016154] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Ariane Stucki
- Department of Biosystems Science and Engineering ETH Zurich Mattenstrasse 26 CH-4058 Basel Switzerland
- National Competence Center in Research (NCCR) Molecular Systems Engineering Basel Switzerland
| | - Jaicy Vallapurackal
- Department of Chemistry University of Basel Mattenstrasse 24a CH-4058 Basel Switzerland
- National Competence Center in Research (NCCR) Molecular Systems Engineering Basel Switzerland
| | - Thomas R. Ward
- Department of Chemistry University of Basel Mattenstrasse 24a CH-4058 Basel Switzerland
- National Competence Center in Research (NCCR) Molecular Systems Engineering Basel Switzerland
| | - Petra S. Dittrich
- Department of Biosystems Science and Engineering ETH Zurich Mattenstrasse 26 CH-4058 Basel Switzerland
- National Competence Center in Research (NCCR) Molecular Systems Engineering Basel Switzerland
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13
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Torbensen K, Baroud CN, Ristori S, Abou-Hassan A. Tip Streaming of a Lipid-Stabilized Double Emulsion Generated in a Microfluidic Channel. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:7442-7448. [PMID: 34110835 DOI: 10.1021/acs.langmuir.1c00827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Water/oil/water (w/o/w) double emulsions (DEs) are multicompartment structures which can be used in many technological applications and in fundamental studies as models of cell like microreactors or templates for other materials. Herein, we study the flow dynamics of water/oil/water double emulsions generated in a microfluidic device and stabilized with the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). We show that by varying the concentration of lipids in the oil phase (chloroform) or by modulating the viscosity of the aqueous continuous phase, the double emulsions under flow exhibit a rich dynamic behavior. An initial deformation of the double emulsions is followed by tube extraction at the rear end, relative to the flow direction, resulting in pinch off at the tube extremity by which small aqueous compartments are released. These compartments are phospholipid vesicles as deduced from fluorescence experiments. The overall process can thus be of help to shed light on the mechanical aspects of phenomena such as the budding and fusion in cell membranes.
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Affiliation(s)
- Kristian Torbensen
- Sorbonne Université, CNRS UMR 8234, Laboratoire PHysico-chimie des Électrolytes et Nanosystèmes InterfaciauX, PHENIX, F-75005 Paris, France
| | - Charles N Baroud
- Physical Microfluidics & Bioengineering, Institut Pasteur, 25 Rue du Dr. Roux, 75015 Paris, France
| | - Sandra Ristori
- Chemistry Department & CSGI, University of Florence, via Della Lastruccia 3, 50019 Sesto Fioretino, Italy
| | - Ali Abou-Hassan
- Sorbonne Université, CNRS UMR 8234, Laboratoire PHysico-chimie des Électrolytes et Nanosystèmes InterfaciauX, PHENIX, F-75005 Paris, France
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14
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Brower KK, Carswell-Crumpton C, Klemm S, Cruz B, Kim G, Calhoun SGK, Nichols L, Fordyce PM. Double emulsion flow cytometry with high-throughput single droplet isolation and nucleic acid recovery. LAB ON A CHIP 2020; 20:2062-2074. [PMID: 32417874 PMCID: PMC7670282 DOI: 10.1039/d0lc00261e] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Droplet microfluidics has made large impacts in diverse areas such as enzyme evolution, chemical product screening, polymer engineering, and single-cell analysis. However, while droplet reactions have become increasingly sophisticated, phenotyping droplets by a fluorescent signal and sorting them to isolate individual variants-of-interest at high-throughput remains challenging. Here, we present sdDE-FACS (s[combining low line]ingle d[combining low line]roplet D[combining low line]ouble E[combining low line]mulsion-FACS), a new method that uses a standard flow cytometer to phenotype, select, and isolate individual double emulsion droplets of interest. Using a 130 μm nozzle at high sort frequency (12-14 kHz), we demonstrate detection of droplet fluorescence signals with a dynamic range spanning 5 orders of magnitude and robust post-sort recovery of intact double emulsion (DE) droplets using 2 commercially-available FACS instruments. We report the first demonstration of single double emulsion droplet isolation with post-sort recovery efficiencies >70%, equivalent to the capabilities of single-cell FACS. Finally, we establish complete downstream recovery of nucleic acids from single, sorted double emulsion droplets via qPCR with little to no cross-contamination. sdDE-FACS marries the full power of droplet microfluidics with flow cytometry to enable a variety of new droplet assays, including rare variant isolation and multiparameter single-cell analysis.
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Affiliation(s)
- Kara K Brower
- Department of Bioengineering, Stanford University, Stanford, California, USA.
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15
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Li P, McClements DJ, Decker EA. Application of Flow Cytometry As Novel Technology in Studying the Effect of Droplet Size on Lipid Oxidation in Oil-in-Water Emulsions. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:567-573. [PMID: 31860290 DOI: 10.1021/acs.jafc.9b04956] [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] [Indexed: 06/10/2023]
Abstract
Despite several published studies, the impact of emulsion droplet size on lipid oxidation rates is unclear. This could be because oil-in-water emulsions are typically polydisperse and the oxidation rate of individual droplets is difficult to discern. Flow cytometry is a technique for studying individual cells and their subpopulations using fluorescence technologies, which is possible to be used in studying individual emulsion droplets. Typical emulsion droplets are too small to be visualized by flow cytometer so emulsions were prepared to have droplets >2 μm that were stabilized by weighting agent and xanthan gum to minimize creaming during storage. A radical-sensitive fluorescence probe (BODIPY665/676) was added to the lipid used to prepare the emulsion so that the susceptibility of individual emulsion droplets could be determined. The results showed that in a polydisperse emulsion system, small droplets were oxidized faster than large droplets. A conventional method was also carried out by blending two emulsions with different droplet sizes and oil densities, and results were in agreement with the observation obtained from flow cytometry. As a new approach, flow cytometry could be utilized in emulsion studies to reveal insights of lipid oxidation mechanisms in individual droplets.
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Affiliation(s)
- Peilong Li
- Department of Food Science , University of Massachusetts , Amherst , Massachusetts 01003 , United States
| | - D Julian McClements
- Department of Food Science , University of Massachusetts , Amherst , Massachusetts 01003 , United States
| | - Eric A Decker
- Department of Food Science , University of Massachusetts , Amherst , Massachusetts 01003 , United States
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Nahar MM, Moon H. Phase separation of multiphase droplets in a digital microfluidic device. MICRO AND NANO SYSTEMS LETTERS 2019. [DOI: 10.1186/s40486-019-0099-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Abstract
This study reports the first comprehensive investigation of separation of the immiscible phases of multiphase droplets in digital microfluidics (DMF) platform. Electrowetting-on-dielectric (EWOD) actuation has been used to mechanically separate the phases. Phase separation performance in terms of percentage residue of one phase into another phase has been quantified. It was conceived that the residue formation can be controlled by controlling the deformation of the phases. The larger capillary number of the neck forming phase is associated with the larger amount of deformation as well as more residue. In this study, we propose two different ways to control the deformation of the phases. In the first method, we applied different EWOD operation voltages on two phases to maintain equal capillary numbers during phase separation. In the second method, while keeping the applied voltages same on both sides, we tested the phase separation performance by varying the actuation schemes. Less than 2% of residue was achieved by both methods, which is almost 90% improvement compared to the phase separation by the conventional droplet splitting technique in EWOD DMF platform, where the residue percentage can go up to 20%.
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Longwell CK, Labanieh L, Cochran JR. High-throughput screening technologies for enzyme engineering. Curr Opin Biotechnol 2017. [DOI: 10.1016/j.copbio.2017.05.012] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Ho KKY, Lee LM, Liu AP. Mechanically activated artificial cell by using microfluidics. Sci Rep 2016; 6:32912. [PMID: 27610921 PMCID: PMC5017192 DOI: 10.1038/srep32912] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 08/17/2016] [Indexed: 01/06/2023] Open
Abstract
All living organisms sense mechanical forces. Engineering mechanosensitive artificial cell through bottom-up in vitro reconstitution offers a way to understand how mixtures of macromolecules assemble and organize into a complex system that responds to forces. We use stable double emulsion droplets (aqueous/oil/aqueous) to prototype mechanosensitive artificial cells. In order to demonstrate mechanosensation in artificial cells, we develop a novel microfluidic device that is capable of trapping double emulsions into designated chambers, followed by compression and aspiration in a parallel manner. The microfluidic device is fabricated using multilayer soft lithography technology, and consists of a control layer and a deformable flow channel. Deflections of the PDMS membrane above the main microfluidic flow channels and trapping chamber array are independently regulated pneumatically by two sets of integrated microfluidic valves. We successfully compress and aspirate the double emulsions, which result in transient increase and permanent decrease in oil thickness, respectively. Finally, we demonstrate the influx of calcium ions as a response of our mechanically activated artificial cell through thinning of oil. The development of a microfluidic device to mechanically activate artificial cells creates new opportunities in force-activated synthetic biology.
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Affiliation(s)
- Kenneth K. Y. Ho
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lap Man Lee
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Allen P. Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan, United States of America
- Biophysics Program, University of Michigan, Ann Arbor, Michigan, United States of America
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Håti AG, Arnfinnsdottir NB, Østevold C, Sletmoen M, Etienne G, Amstad E, Stokke BT. Microarrays for the study of compartmentalized microorganisms in alginate microbeads and (W/O/W) double emulsions. RSC Adv 2016. [DOI: 10.1039/c6ra23945e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Here, we present two array platforms for small (50–100 μm) cell-containing 3D compartments prepared by droplet-based microfluidics.
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Affiliation(s)
- Armend G. Håti
- Biophysics and Medical Technology
- Dept. of Physics
- NTNU
- Norwegian University of Science and Technology
- NO-7491 Trondheim
| | - Nina Bjørk Arnfinnsdottir
- Biophysics and Medical Technology
- Dept. of Physics
- NTNU
- Norwegian University of Science and Technology
- NO-7491 Trondheim
| | - Camilla Østevold
- Biophysics and Medical Technology
- Dept. of Physics
- NTNU
- Norwegian University of Science and Technology
- NO-7491 Trondheim
| | - Marit Sletmoen
- Dept. of Biotechnology
- NTNU
- Norwegian University of Science and Technology
- NO-7491 Trondheim
- Norway
| | - Gianluca Etienne
- Soft Materials Laboratory (SMaL)
- Institute of Materials
- École Polytechnique Fédérale de Lausanne
- 1015 Lausanne
- Switzerland
| | - Esther Amstad
- Soft Materials Laboratory (SMaL)
- Institute of Materials
- École Polytechnique Fédérale de Lausanne
- 1015 Lausanne
- Switzerland
| | - Bjørn T. Stokke
- Biophysics and Medical Technology
- Dept. of Physics
- NTNU
- Norwegian University of Science and Technology
- NO-7491 Trondheim
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