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Xu H, Wang T, Che Z. Coalescence of immiscible droplets in liquid environments. J Colloid Interface Sci 2024; 659:60-70. [PMID: 38157727 DOI: 10.1016/j.jcis.2023.12.103] [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: 08/04/2023] [Revised: 12/01/2023] [Accepted: 12/16/2023] [Indexed: 01/03/2024]
Abstract
HYPOTHESIS Droplet coalescence process is important in many applications and has been studied extensively when two droplets are surrounded by gas. However, the coalescence dynamics would be different when the two droplets are surrounded by an external viscous liquid. The coalescence of immiscible droplets in liquids has not been explored. EXPERIMENTS In the present research, the coalescence of two immiscible droplets in low- and high-viscosity liquids is investigated and compared with their miscible counterparts experimentally. The coalescence dynamics is investigated via high-speed imaging, and theoretical models are proposed to analyze the growth of the liquid bridge. FINDINGS We find that, the liquid bridge r evolves differently due to the constraint from the triple line in the bridge region, which follows r∝t2/3 for low-viscosity surroundings. While for high-viscosity surroundings, the liquid bridge grows at a constant velocity ur which varies with the surrounding viscosity μs as [Formula: see text] . In the later stage of the bridge growth, the bridge evolution again merges with the well-established power-law regime r∝t1/2, being either in low or high-viscosity liquids. Moreover, a new inertia-viscous-capillary timescale is proposed, which unifies the combined influence of inertia, viscous, and capillary forces on the evolution of the liquid bridge in liquid environments, highlighting the joint role of inertia and viscous resistance in the coalescence process.
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Affiliation(s)
- Huadan Xu
- State Key Laboratory of Engines, Tianjin University, Tianjin, 300350, China
| | - Tianyou Wang
- State Key Laboratory of Engines, Tianjin University, Tianjin, 300350, China; National Industry-Education Platform of Energy Storage, Tianjin University, Tianjin, 300350, China
| | - Zhizhao Che
- State Key Laboratory of Engines, Tianjin University, Tianjin, 300350, China; National Industry-Education Platform of Energy Storage, Tianjin University, Tianjin, 300350, China.
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2
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Liu W, Park JM. Numerical study on the engulfing behavior between immiscible droplets in a confined shear flow. Chem Eng Sci 2022. [DOI: 10.1016/j.ces.2022.118265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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3
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Gas–liquid–liquid slug flow and mass transfer in hydrophilic and hydrophobic microreactors. Chin J Chem Eng 2022. [DOI: 10.1016/j.cjche.2022.07.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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4
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Ebadi A, Hosseinalipour S. The collision of immiscible droplets in three-phase liquid systems: A numerical study using phase-field lattice Boltzmann method. Chem Eng Res Des 2022. [DOI: 10.1016/j.cherd.2021.12.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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5
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Hassan MR, Wang C. Ferro-hydrodynamic interactions between ferrofluid droplet pairs in simple shear flows. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.124906] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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6
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Agnihotri SN, Raveshi MR, Bhardwaj R, Neild A. Microfluidic Valves for Selective on-Chip Droplet Splitting at Multiple Sites. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:1138-1146. [PMID: 31968938 DOI: 10.1021/acs.langmuir.9b03515] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We describe a microfluidic system for control of droplet division at two locations using a T-junction and expansion channel which are placed one after another. Droplets generated at a standard T-junction are introduced into the droplet division section of the microchannel. In the first set of experiments, the droplet division section consists of two consecutive identical T-junctions branching from the main channel. With this geometry, we were able to produce daughter droplets only at the first junction while there was no droplet division at the second junction. Resistive network analysis is used to redesign the microchannel geometry with an expansion channel in place of the second junction, to have the same quantity of flow entering in both the junctions. We observed five different regimes of droplet breakup, namely, (1) no droplet breakup in both junctions, (2) droplet breakup in the first junction, (3) droplet breakup in both junctions with higher daughter droplet volume in the first junction, (4) daughter droplet volume higher in the second junction, and (5) intermittent droplet breakup in both the junctions. Under specific flow conditions, droplet interaction with both the junctions is similar. We then showed design requirements for location of microvalves, simulated by deformation of the main channel wall and by experiments to break the droplet.
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Affiliation(s)
- Sagar N Agnihotri
- IITB-Monash Research Academy , IIT Bombay , Mumbai 400076 , India
- Department of Mechanical and Aerospace Engineering , Monash University , Melbourne , Victoria 3800 , Australia
- Department of Mechanical Engineering , Indian Institute of Technology Bombay , Mumbai 400076 , India
| | - Mohammad Reza Raveshi
- Department of Mechanical and Aerospace Engineering , Monash University , Melbourne , Victoria 3800 , Australia
| | - Rajneesh Bhardwaj
- Department of Mechanical Engineering , Indian Institute of Technology Bombay , Mumbai 400076 , India
| | - Adrian Neild
- Department of Mechanical and Aerospace Engineering , Monash University , Melbourne , Victoria 3800 , Australia
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7
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Manipulation of gas-liquid-liquid systems in continuous flow microreactors for efficient reaction processes. J Flow Chem 2020. [DOI: 10.1007/s41981-019-00062-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AbstractGas-liquid-liquid flow in microreactors holds great potential towards process intensification of operation in multiphase systems, particularly by a precise control over the three-phase contact patterns and the associated mass transfer enhancement. This work reviews the manipulation of gas-liquid-liquid three-phase flow in microreactors for carrying out efficient reaction processes, including gas-liquid-liquid reactions with catalysts residing in either liquid phase, coupling of a gas-liquid reaction with the liquid-liquid extraction, inert gas assisted liquid-liquid reactions and particle synthesis under three-phase flow. Microreactors are shown to be able to provide well-defined flow patterns and enhanced gas-liquid/liquid-liquid mass transfer rates towards the optimized system performance. The interplay between hydrodynamics and mass transfer, as well as its influence on the overall microreactor system performance is discussed. Meanwhile, future perspectives regarding the scale-up of gas-liquid-liquid microreactors in order to meet the industrial needs and their potential applications especially in biobased chemicals and fuels synthesis are further addressed.
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8
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Continuous Generation of Millimeter-Sized Glycine Crystals in Non-Seeded Millifluidic Slug Flow. CRYSTALS 2019. [DOI: 10.3390/cryst9080412] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Millimeter-sized α-glycine crystals were generated from continuous non-seeded cooling crystallization in slug flow. The crystallization process is composed of three steps in sequence: slug formation, crash-cooling nucleation, and growth. Stable uniform slugs of three different aspect ratios (slug length/tubing inner diameter) were formed, by adjusting the flow rates of both the solution and air streams. Besides supersaturation, the slug aspect ratio can also affect primary nucleation outcome. Stable slug flow can accommodate a relative supersaturation (C/C*) of up to 1.5 without secondary nucleation. Large glycine crystals can grow to millimeter size within 10 min, inside millimeter-sized slugs without reducing the slug quality.
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9
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10
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Hsieh K, Zec HC, Chen L, Kaushik AM, Mach KE, Liao JC, Wang TH. Simple and Precise Counting of Viable Bacteria by Resazurin-Amplified Picoarray Detection. Anal Chem 2018; 90:9449-9456. [PMID: 29969556 DOI: 10.1021/acs.analchem.8b02096] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Simple, fast, and precise counting of viable bacteria is fundamental to a variety of microbiological applications such as food quality monitoring and clinical diagnosis. To this end, agar plating, microscopy, and emerging microfluidic devices for single bacteria detection have provided useful means for counting viable bacteria, but they also have their limitations ranging from complexity, time, and inaccuracy. We present herein our new method RAPiD (Resazurin-Amplified Picoarray Detection) for addressing this important problem. In RAPiD, we employ vacuum-assisted sample loading and oil-driven sample digitization to stochastically confine single bacteria in Picoarray, a microfluidic device with picoliter-sized isolation chambers (picochambers), in <30 s with only a few minutes of hands-on time. We add AlamarBlue, a resazurin-based fluorescent dye for bacterial growth, in our assay to accelerate the detection of "microcolonies" proliferated from single bacteria within picochambers. Detecting fluorescence in picochambers as an amplified surrogate for bacterial cells allows us to count hundreds of microcolonies with a single image taken via wide-field fluorescence microscopy. We have also expanded our method to practically test multiple titrations from a single bacterial sample in parallel. Using this expanded "multi-RAPiD" strategy, we can quantify viable cells in E. coli and S. aureus samples with precision in ∼3 h, illustrating RAPiD as a promising new method for counting viable bacteria for microbiological applications.
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Affiliation(s)
- Kuangwen Hsieh
- Department of Mechanical Engineering , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Helena C Zec
- Department of Biomedical Engineering , Johns Hopkins School of Medicine , Baltimore , Maryland 21205 , United States
| | - Liben Chen
- Department of Mechanical Engineering , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Aniruddha M Kaushik
- Department of Mechanical Engineering , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Kathleen E Mach
- Department of Urology , Stanford University School of Medicine , Stanford , California 94305 , United States
| | - Joseph C Liao
- Department of Urology , Stanford University School of Medicine , Stanford , California 94305 , United States
| | - Tza-Huei Wang
- Department of Mechanical Engineering , Johns Hopkins University , Baltimore , Maryland 21218 , United States.,Department of Biomedical Engineering , Johns Hopkins School of Medicine , Baltimore , Maryland 21205 , United States
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Eduati F, Utharala R, Madhavan D, Neumann UP, Longerich T, Cramer T, Saez-Rodriguez J, Merten CA. A microfluidics platform for combinatorial drug screening on cancer biopsies. Nat Commun 2018; 9:2434. [PMID: 29934552 PMCID: PMC6015045 DOI: 10.1038/s41467-018-04919-w] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 06/05/2018] [Indexed: 02/06/2023] Open
Abstract
Screening drugs on patient biopsies from solid tumours has immense potential, but is challenging due to the small amount of available material. To address this, we present here a plug-based microfluidics platform for functional screening of drug combinations. Integrated Braille valves allow changing the plug composition on demand and enable collecting >1200 data points (56 different conditions with at least 20 replicates each) per biopsy. After deriving and validating efficient and specific drug combinations for two genetically different pancreatic cancer cell lines and xenograft mouse models, we additionally screen live cells from human solid tumours with no need for ex vivo culturing steps, and obtain highly specific sensitivity profiles. The entire workflow can be completed within 48 h at assay costs of less than US$ 150 per patient. We believe this can pave the way for rapid determination of optimal personalized cancer therapies.
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Affiliation(s)
- Federica Eduati
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genome Campus, Hinxton, CB10 1SD, Cambridge, United Kingdom
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, 69117, Heidelberg, Germany
- Department of Biomedical Engineering, Eindhoven University of Technology, 5600MB, Eindhoven, The Netherlands
| | - Ramesh Utharala
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Dharanija Madhavan
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Ulf Peter Neumann
- Department of Surgery, RWTH University Hospital, 52057, Aachen, Germany
- ESCAM - European Surgery Center Aachen Maastricht, Aachen, Germany and Maastricht, The Netherlands
| | - Thomas Longerich
- Institute of Pathology, RWTH University Hospital, 52057, Aachen, Germany
- Institute of Pathology, University Hospital Heidelberg, 69120, Heidelberg, Germany
| | - Thorsten Cramer
- ESCAM - European Surgery Center Aachen Maastricht, Aachen, Germany and Maastricht, The Netherlands
- Molecular Tumor Biology, Department Surgery, RWTH University Hospital, 52057, Aachen, Germany
| | - Julio Saez-Rodriguez
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genome Campus, Hinxton, CB10 1SD, Cambridge, United Kingdom.
- Joint Research Centre for Computational Biomedicine (JRC-COMBINE), RWTH Aachen University, Faculty of Medicine, 52057, Aachen, Germany.
- Institute for Computational Biomedicine, Heidelberg University, Faculty of Medicine, BIOQUANT-Center, 69120, Heidelberg, Germany.
| | - Christoph A Merten
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, 69117, Heidelberg, Germany.
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12
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Prastowo A, Feuerborn A, Cook PR, Walsh EJ. Biocompatibility of fluids for multiphase drops-in-drops microfluidics. Biomed Microdevices 2017; 18:114. [PMID: 27921279 PMCID: PMC5138278 DOI: 10.1007/s10544-016-0137-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
This paper addresses the biocompatibility of fluids and surfactants in the context of microfluidics and more specifically in a drops-in-drops system for mammalian cell based drug screening. In the drops-in-drops approach, three immiscible fluids are used to manipulate the flow of aqueous microliter-sized drops; it enables merging of drops containing cells with drops containing drugs within a Teflon tube. Preliminary tests showed that a commonly-used fluid and surfactant combination resulted in significant variability in gene expression levels in Jurkat cells after exposure to a drug for four hours. This result led to further investigations of potential fluid and surfactant combinations that can be used in microfluidic systems for medium to long-term drug screening. Results herein identify a fluid combination, HFE-7500 and 5-cSt silicone oil + 0.25% Abil EM180, which enabled the drops-in-drops approach; this combination also allowed gene expression at normal levels comparable with the conventional drug screening in both magnitude and variability.
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Affiliation(s)
- Aishah Prastowo
- Osney Thermo-Fluids Laboratory, Department of Engineering Science, University of Oxford, Osney Mead, Oxford, OX2 0ES, UK
| | - Alexander Feuerborn
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Peter R Cook
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Edmond J Walsh
- Osney Thermo-Fluids Laboratory, Department of Engineering Science, University of Oxford, Osney Mead, Oxford, OX2 0ES, UK.
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13
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Abolhasani M, Jensen KF. Oscillatory multiphase flow strategy for chemistry and biology. LAB ON A CHIP 2016; 16:2775-2784. [PMID: 27397146 DOI: 10.1039/c6lc00728g] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Continuous multiphase flow strategies are commonly employed for high-throughput parameter screening of physical, chemical, and biological processes as well as continuous preparation of a wide range of fine chemicals and micro/nano particles with processing times up to 10 min. The inter-dependency of mixing and residence times, and their direct correlation with reactor length have limited the adaptation of multiphase flow strategies for studies of processes with relatively long processing times (0.5-24 h). In this frontier article, we describe an oscillatory multiphase flow strategy to decouple mixing and residence times and enable investigation of longer timescale experiments than typically feasible with conventional continuous multiphase flow approaches. We review current oscillatory multiphase flow technologies, provide an overview of the advancements of this relatively new strategy in chemistry and biology, and close with a perspective on future opportunities.
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Affiliation(s)
- Milad Abolhasani
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, 66-342, Cambridge, MA 02139, USA.
| | - Klavs F Jensen
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, 66-342, Cambridge, MA 02139, USA.
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14
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Lestari G, Salari A, Abolhasani M, Kumacheva E. A microfluidic study of liquid-liquid extraction mediated by carbon dioxide. LAB ON A CHIP 2016; 16:2710-2718. [PMID: 27327198 DOI: 10.1039/c6lc00597g] [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
Liquid-liquid extraction is an important separation and purification method; however, it faces a challenge in reducing the energy consumption and the environmental impact of solvent (extractant) recovery. The reversible chemical reactions of switchable solvents (nitrogenous bases) with carbon dioxide (CO2) can be implemented in reactive liquid-liquid extraction to significantly reduce the cost and energy requirements of solvent recovery. The development of new effective switchable solvents reacting with CO2 and the optimization of extraction conditions rely on the ability to evaluate and screen the performance of switchable solvents in extraction processes. We report a microfluidic strategy for time- and labour-efficient studies of CO2-mediated solvent extraction. The platform utilizes a liquid segment containing an aqueous extractant droplet and a droplet of a solution of a switchable solvent in a non-polar liquid, with gaseous CO2 supplied to the segment from both sides. Following the reaction of the switchable solvent with CO2, the solvent becomes hydrophilic and transfers from the non-polar solvent to the aqueous droplet. By monitoring the time-dependent variation in droplet volumes, we determined the efficiency and extraction time for the CO2-mediated extraction of different nitrogenous bases in a broad experimental parameter space. The platform enables a significant reduction in the amount of switchable solvents used in these studies, provides accurate temporal characterization of the liquid-liquid extraction process, and offers the capability of high-throughput screening of switchable solvents.
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Affiliation(s)
- Gabriella Lestari
- Department of Chemical Engineering, University of Toronto, 200 College Street, Toronto, ON M5S 3E5, Canada
| | - Alinaghi Salari
- Department of Chemical Engineering, University of Toronto, 200 College Street, Toronto, ON M5S 3E5, Canada
| | - Milad Abolhasani
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Building 66-525, Cambridge, MA 02139, USA.
| | - Eugenia Kumacheva
- Department of Chemical Engineering, University of Toronto, 200 College Street, Toronto, ON M5S 3E5, Canada and Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, ON M5S 3H6, Canada. and Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9, Canada
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15
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Zhang Y, Shitta A, Meredith JC, Behrens SH. Bubble Meets Droplet: Particle-Assisted Reconfiguration of Wetting Morphologies in Colloidal Multiphase Systems. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2016; 12:3309-3319. [PMID: 27167839 DOI: 10.1002/smll.201600799] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Indexed: 06/05/2023]
Abstract
Wetting phenomena are ubiquitous in nature and play key functions in various industrial processes and products. When a gas bubble encounters an oil droplet in an aqueous medium, it can experience either partial wetting or complete engulfment by the oil. Each of these morphologies can have practical benefits, and controlling the morphology is desirable for applications ranging from particle synthesis to oil recovery and gas flotation. It is known that the wetting of two fluids within a fluid medium depends on the balance of interfacial tensions and can thus be modified with surfactant additives. It is reported that colloidal particles, too, can be used to promote both wetting and dewetting in multifluid systems. This study demonstrates the surfactant-free tuning and dynamic reconfiguration of bubble-droplet morphologies with the help of cellulosic particles. It further shows that the effect can be attributed to particle adsorption at the fluid interfaces, which can be probed by interfacial tensiometry, making particle-induced transitions in the wetting morphology predictable. Finally, particle adsorption at different rates to air-water and oil-water interfaces can even lead to slow, reentrant wetting behavior not familiar from particle-free systems.
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Affiliation(s)
- Yi Zhang
- School of Chemical & Biomoelcular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0100, USA
| | - Abiola Shitta
- School of Chemical & Biomoelcular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0100, USA
| | - J Carson Meredith
- School of Chemical & Biomoelcular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0100, USA
| | - Sven H Behrens
- School of Chemical & Biomoelcular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0100, USA
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Abolhasani M, Coley CW, Jensen KF. Multiphase Oscillatory Flow Strategy for in Situ Measurement and Screening of Partition Coefficients. Anal Chem 2015; 87:11130-6. [DOI: 10.1021/acs.analchem.5b03311] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Milad Abolhasani
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, 66-342, Cambridge, Massachusetts 02139, United States
| | - Connor W. Coley
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, 66-342, Cambridge, Massachusetts 02139, United States
| | - Klavs F. Jensen
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, 66-342, Cambridge, Massachusetts 02139, United States
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Hwang JW, Choi JH, Choi B, Lee G, Lee SW, Koo YM, Chang WJ. Microfluidic room temperature ionic liquid droplet generation depending on the hydrophobicity and interfacial tension. KOREAN J CHEM ENG 2015. [DOI: 10.1007/s11814-015-0037-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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18
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Aubry G, Zhan M, Lu H. Hydrogel-droplet microfluidic platform for high-resolution imaging and sorting of early larval Caenorhabditis elegans. LAB ON A CHIP 2015; 15:1424-31. [PMID: 25622546 PMCID: PMC4348330 DOI: 10.1039/c4lc01384k] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The nematode Caenorhabditis elegans is an important model organism in research on neuroscience and development because of its stereotyped anatomy, relevance to human biology, and ease of culture and genetic manipulation. The first larval stage (L1) is of particular interest in many biological problems, including post-embryonic developmental processes and developmental decision-making, such as dauer formation. However, L1's small size and high mobility make it difficult to manipulate; particularly in microfluidic chips, which have been used to great advantage in handling larger larvae and adult animals, small features are difficult to fabricate and these structures often get clogged easily, making the devices less robust. We have developed a microfluidic device to overcome these challenges and enable high-resolution imaging and sorting of early larval stage C. elegans via encapsulation in droplets of a thermosensitive hydrogel. To achieve precise handling of early larval stage worms, we demonstrated on-chip production, storage, and sorting of hydrogel droplets. We also demonstrated temporary immobilization of the worms within the droplets, allowing high-resolution imaging with minimal physiological perturbations. Because of the ability to array hydrogel droplets for handling a large number of L1 worms in a robust way, we envision that this platform will be widely applicable to screening in various developmental studies.
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Affiliation(s)
- Guillaume Aubry
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, Georgia 30332, USA.
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Wang K, Qin K, Lu Y, Luo G, Wang T. Gas/liquid/liquid three-phase flow patterns and bubble/droplet size laws in a double T-junction microchannel. AIChE J 2015. [DOI: 10.1002/aic.14758] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Kai Wang
- The State Key Laboratory of Chemical Engineering, Dept. of Chemical Engineering; Tsinghua University; Beijing 100084 China
| | - Kang Qin
- The State Key Laboratory of Chemical Engineering, Dept. of Chemical Engineering; Tsinghua University; Beijing 100084 China
| | - Yangcheng Lu
- The State Key Laboratory of Chemical Engineering, Dept. of Chemical Engineering; Tsinghua University; Beijing 100084 China
| | - Guangsheng Luo
- The State Key Laboratory of Chemical Engineering, Dept. of Chemical Engineering; Tsinghua University; Beijing 100084 China
| | - Tao Wang
- The State Key Laboratory of Chemical Engineering, Dept. of Chemical Engineering; Tsinghua University; Beijing 100084 China
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Feuerborn A, Prastowo A, Cook PR, Walsh E. Merging drops in a Teflon tube, and transferring fluid between them, illustrated by protein crystallization and drug screening. LAB ON A CHIP 2015; 15:3766-3775. [PMID: 26246015 DOI: 10.1039/c5lc00726g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The ability to manipulate drops with small volumes has many practical applications. Current microfluidic devices generally exploit channel geometry and/or active external equipment to control drops. Here we use a Teflon tube attached to a syringe pump and exploit the properties of interfaces between three immiscible liquids to create particular fluidic architectures. We then go on to merge any number of drops (with volumes of micro- to nano-liters) at predefined points in time and space in the tube; for example, 51 drops were merged in a defined order to yield one large drop. Using a different architecture, specified amounts of fluid were transferred between 2 nl drops at specified rates; for example, 2.5 pl aliquots were transferred (at rates of ~500 fl s(-1)) between two drops through inter-connecting nano-channels (width ~40 nm). One proof-of-principle experiment involved screening conditions required to crystallize a protein (using a concentration gradient created using such nano-channels). Another demonstrated biocompatibility; drugs were mixed with human cells grown in suspension or on surfaces, and the treated cells responded like those grown conventionally. Although most experiments were performed manually, moderate high-throughput potential was demonstrated by mixing ~1000 different pairs of 50 nl drops in ~15 min using a robot. We suggest this reusable, low-cost, and versatile methodology could facilitate the introduction of microfluidics into workflows of many experimental laboratories.
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Affiliation(s)
- A Feuerborn
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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Three-Phase Permeabilities: Upscaling, Analytical Solutions and Uncertainty Analysis in Elementary Pore Structures. Transp Porous Media 2014. [DOI: 10.1007/s11242-014-0400-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Nightingale AM, Phillips TW, Bannock JH, de Mello JC. Controlled multistep synthesis in a three-phase droplet reactor. Nat Commun 2014; 5:3777. [PMID: 24797034 PMCID: PMC4024758 DOI: 10.1038/ncomms4777] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 04/02/2014] [Indexed: 12/26/2022] Open
Abstract
Channel-fouling is a pervasive problem in continuous flow chemistry, causing poor product control and reactor failure. Droplet chemistry, in which the reaction mixture flows as discrete droplets inside an immiscible carrier liquid, prevents fouling by isolating the reaction from the channel walls. Unfortunately, the difficulty of controllably adding new reagents to an existing droplet stream has largely restricted droplet chemistry to simple reactions in which all reagents are supplied at the time of droplet formation. Here we describe an effective method for repeatedly adding controlled quantities of reagents to droplets. The reagents are injected into a multiphase fluid stream, comprising the carrier liquid, droplets of the reaction mixture and an inert gas that maintains a uniform droplet spacing and suppresses new droplet formation. The method, which is suited to many multistep reactions, is applied to a five-stage quantum dot synthesis wherein particle growth is sustained by repeatedly adding fresh feedstock.
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Affiliation(s)
- Adrian M Nightingale
- 1] Department of Chemistry, Imperial College London, Exhibition Road, South Kensington, London SW7 2AY, UK [2]
| | - Thomas W Phillips
- Department of Chemistry, Imperial College London, Exhibition Road, South Kensington, London SW7 2AY, UK
| | - James H Bannock
- Department of Chemistry, Imperial College London, Exhibition Road, South Kensington, London SW7 2AY, UK
| | - John C de Mello
- Department of Chemistry, Imperial College London, Exhibition Road, South Kensington, London SW7 2AY, UK
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23
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Um E, Rogers ME, Stone HA. Combinatorial generation of droplets by controlled assembly and coalescence. LAB ON A CHIP 2013; 13:4674-4680. [PMID: 24132051 DOI: 10.1039/c3lc50957e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We describe a microfluidic system for generating a sequence of liquid droplets of multiple concentrations in a single experimental condition. The series of final droplets has the combination of the compositions varying periodically, with polydispersity of the size less than 8%. By utilizing the design of the microchannel geometry and the passive control of three immiscible fluids (oil, water, and air) including generation, breakup, separation and coalescence of droplets, we can change the system to generate diverse sets of combination of materials. The device can be used for testing different concentration of materials in picoliter volumes and developing a new way to deliver dynamic signals of chemicals with microfluidics.
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Affiliation(s)
- Eujin Um
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA.
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24
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Cech J, Přibyl M, Snita D. Three-phase slug flow in microchips can provide beneficial reaction conditions for enzyme liquid-liquid reactions. BIOMICROFLUIDICS 2013; 7:54103. [PMID: 24404066 PMCID: PMC3785521 DOI: 10.1063/1.4821168] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 08/30/2013] [Indexed: 05/31/2023]
Abstract
Here, we introduce a solution to low stability of a two-phase slug flow with a chemical reaction occurring at the phase interface in a microfluidic reactor where substantial merging of individual reacting slugs results in the loss of uniformity of the flow. We create a three-phase slug flow by introducing a third fluid phase into the originally two-phase liquid-liquid slug flow, which generates small two-phase liquid slugs separated by gas phase. Introduction of the third phase into our system efficiently prevents merging of slugs and provides beneficial reaction conditions, such as uniform flow pattern along the whole reaction capillary, interfacial area with good reproducibility, and intensive water-oil interface renewal. We tested the three-phase flow on an enzyme hydrolysis of soybean oil and compared the reaction conversion with those from unstable two-phase slug flows. We experimentally confirmed that the three-phase slug flow arrangement provides conversions and pressure drops comparable or even better with two-phase liquid-liquid arrangements.
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Affiliation(s)
- Jiří Cech
- Department of Chemical Engineering, Institute of Chemical Technology, Technická 5, 166 28 Prague, Czech Republic
| | - Michal Přibyl
- Department of Chemical Engineering, Institute of Chemical Technology, Technická 5, 166 28 Prague, Czech Republic ; Research Centre New Technologies, University of West Bohemia, Univerzitní 8, 306 14 Plzeň, Czech Republic
| | - Dalimil Snita
- Department of Chemical Engineering, Institute of Chemical Technology, Technická 5, 166 28 Prague, Czech Republic ; Research Centre New Technologies, University of West Bohemia, Univerzitní 8, 306 14 Plzeň, Czech Republic
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25
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Shardt O, Derksen JJ, Mitra SK. Simulations of droplet coalescence in simple shear flow. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:6201-6212. [PMID: 23642079 DOI: 10.1021/la304919p] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Simulating droplet coalescence is challenging because small-scale (tens of nanometers) phenomena determine the behavior of much larger (micrometer- to millimeter-scale) droplets. In general, liquid droplets colliding in a liquid medium coalesce when the capillary number is less than a critical value. We present simulations of droplet collisions and coalescence in simple shear flow using the free-energy binary-liquid lattice Boltzmann method. In previous simulations of low-speed collisions, droplets coalesced at unrealistically high capillary numbers. Simulations of noncoalescing droplets have not been reported, and therefore, the critical capillary number for simulated collisions was unknown. By simulating droplets with radii up to 100 lattice nodes, we determine the critical capillary number for coalescence and quantify the effects of several numerical and geometric parameters. The simulations were performed with a well-resolved interface, a Reynolds number of one, and capillary numbers from 0.01 to 0.2. The ratio of the droplet radius and interface thickness has the greatest effect on the critical capillary number. As in experiments, the critical capillary number decreases with increasing droplet size. A second numerical parameter, the interface diffusivity (Péclet number) also influences the conditions for coalescence: coalescence occurs at higher capillary numbers with lower Péclet numbers (higher diffusivity). The effects of the vertical offset between the droplets and the confinement of the droplets were also studied. Physically reasonable results were obtained and provide insight into the conditions for coalescence. Simulations that match the conditions of experiments reported in the literature remain computationally impractical. However, the scale of the simulations is now sufficiently large that a comparison with experiments involving smaller droplets (≈10 μm) and lower viscosities (≈10(-6) m(2)/s, the viscosity of water) may be possible. Experiments at these conditions are therefore needed to determine the interface thickness and Péclet number that should be used for predictive simulations of coalescence phenomena.
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Affiliation(s)
- Orest Shardt
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton AB T6G 2V4, Canada.
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27
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Goyal S, Thorson MR, Schneider CL, Zhang GGZ, Gong Y, Kenis PJA. A microfluidic platform for evaporation-based salt screening of pharmaceutical parent compounds. LAB ON A CHIP 2013; 13:1708-1723. [PMID: 23478750 DOI: 10.1039/c3lc41271g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We describe a microfluidic platform to screen for salt forms of pharmaceutical compounds (PCs) via controlled evaporation. The platform enables on-chip combinatorial mixing of PC and salt former solutions in a 24-well array (~200 nL/well), which is a drastic reduction in the amount of PC needed per condition screened compared to traditional screening approaches that require ~100 μL/well. The reduced sample needs enable salt screening at a much earlier stage in the drug development process, when only limited quantities of PCs are available. Compatibility with (i) solvents commonly used in the pharmaceutical industry, and (ii) Raman spectroscopy for solid form identification was ensured by using a hybrid microfluidic platform. A thin layer of elastomeric PDMS was utilized to retain pneumatic valving capabilities. This layer is sandwiched between layers of cyclic-olefin copolymer, a material with low air and solvent permeability and low Raman background to yield a physically rigid and Raman compatible chip. A solvent-impermeable thiolene layer patterned with evaporation channels permits control over the rate of solvent evaporation. Control over the rate of solvent evaporation (2-15 nL h(-1)) results in consistent, known rates of increase in the supersaturation levels attained on-chip, and increases the probability for crystalline solids to form. The modular nature of the platform enables on-chip Raman and birefringence analysis of the solid forms. Model compounds, tamoxifen and ephedrine, were used to validate the platform's ability to screen for salts. On-chip Raman analysis helped to identify six different salts each of tamoxifen and ephedrine.
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Affiliation(s)
- Sachit Goyal
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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28
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Abstract
Droplet-based microfluidics or digital microfluidics is a subclass of microfluidic devices, wherein droplets are generated using active or passive methods. The active method for generation of droplets involves the use of an external factor such as an electric field for droplet generation. Two techniques that fall in this category are dielectrophoresis (DEP) and electrowetting on dielectric (EWOD). In passive methods, the droplet generation depends on the geometry and dimensions of the device. T-junction and flow focusing methods are examples of passive methods used for generation of droplets. In this chapter the methods used for droplet generation, mixing of contents of droplets, and the manipulation of droplets are described in brief. A review of the applications of digital microfluidics with emphasis on the last decade is presented.
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Affiliation(s)
- Sanjiv Sharma
- Institute of Biomedical Engineering & Department of Chemistry, Imperial College, London, UK.
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29
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Barikbin Z, Rahman T, Khan SA. Fireflies-on-a-chip: (ionic liquid)-aqueous microdroplets for biphasic chemical analysis. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2012; 8:2152-2157. [PMID: 22514126 DOI: 10.1002/smll.201102748] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 01/30/2012] [Indexed: 05/31/2023]
Affiliation(s)
- Zahra Barikbin
- Singapore-MIT Alliance, National University of Singapore, 4 Engineering Drive 3, E4-04-10, 117576 Singapore
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30
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Abstract
In the present paper, we review and discuss current developments and challenges in the field of droplet-based microfluidics. This discussion includes an assessment of the basic fluid dynamics of segmented flows, material requirements, fundamental unit operations and how integration of functional components can be applied to specific biological problems.
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31
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Scheeline A, Behrens RL. Potential of levitated drops to serve as microreactors for biophysical measurements. Biophys Chem 2012; 165-166:1-12. [DOI: 10.1016/j.bpc.2012.03.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 03/18/2012] [Accepted: 03/18/2012] [Indexed: 01/15/2023]
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32
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Thorson MR, Goyal S, Schudel BR, Zukoski CF, Zhang GGZ, Gong Y, Kenis PJA. A microfluidic platform for pharmaceutical salt screening. LAB ON A CHIP 2011; 11:3829-37. [PMID: 21956673 DOI: 10.1039/c1lc20645a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We describe a microfluidic platform comprised of 48 wells to screen for pharmaceutical salts. Solutions of pharmaceutical parent compounds (PCs) and salt formers (SFs) are mixed on-chip in a combinatorial fashion in arrays of 87.5-nanolitre wells, which constitutes a drastic reduction of the volume of PC solution needed per condition screened compared to typical high throughput pharmaceutical screening approaches. Nucleation and growth of salt crystals is induced by diffusive and/or convective mixing of solutions containing, respectively, PCs and SFs in a variety of solvents. To enable long term experiments, solvent loss was minimized by reducing the thickness of the absorptive polymeric material, polydimethylsiloxane (PDMS), and by using solvent impermeable top and bottom layers. Additionally, well isolation was enhanced via the incorporation of pneumatic valves that are closed at rest. Brightfield and polarized light microscopy and Raman spectroscopy were used for on-chip analysis and crystal identification. Using a gold-coated glass substrate and minimizing the thickness of the PDMS control layer drastically improved the signal-to-noise ratio for Raman spectra. Two drugs, naproxen (acid) and ephedrine (base), were used for validation of the platform's ability to screen for salts. Each PC was mixed combinatorially with potential SFs in a variety of solvents. Crystals were visualized using brightfield polarized light microscopy. Subsequent on-chip analyses of the crystals with Raman spectroscopy identified four different naproxen salts and five different ephedrine salts.
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Affiliation(s)
- Michael R Thorson
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, USA
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33
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Wang JT, Wang J, Han JJ. Fabrication of advanced particles and particle-based materials assisted by droplet-based microfluidics. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2011; 7:1728-54. [PMID: 21618428 DOI: 10.1002/smll.201001913] [Citation(s) in RCA: 177] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 01/17/2011] [Indexed: 05/06/2023]
Abstract
Recent advances in the fabrication of complex particles and particle-based materials assisted by droplet-based microfluidics are reviewed. Monodisperse particles with expected internal structures, morphologies, and sizes in the range of nanometers to hundreds of micrometers have received a good deal of attention in recent years. Due to the capability of generating monodisperse emulsions and of executing precise control and operations on the suspended droplets inside the microchannels, droplet-based microfluidic devices have become powerful tools for fabricating complex particles with desired properties. Emulsions and multiple-emulsions generated in the microfluidic devices can be composed of a variety of materials including aqueous solutions, gels, polymers and solutions containing functional nanoparticles. They are ideal microreactors or fine templates for synthesizing advanced particles, such as polymer particles, microcapsules, nanocrystals, and photonic crystal clusters or beads by further chemical or physical operations. These particles are promising materials that may be applicable for many fields, such as photonic materials, drug delivery systems, and bio-analysis. From simple to complex, from spherical to nonspherical, from polymerization and reaction crystallization to self-assembly, this review aims to help readers be aware of the many aspects of this field.
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Affiliation(s)
- Jing-Tao Wang
- School of Chemical Engineering and Technology & State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin, P. R. China, 300072.
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34
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35
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Lee SH, Heinz AJ, Choi SE, Park W, Kwon S. Polymer based chemical delivery to multichannel capillary patterned cells. LAB ON A CHIP 2011; 11:605-608. [PMID: 21240397 DOI: 10.1039/c0lc00328j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In order to match the controllability of traditional pipetting with the advantages of microfluidics, we introduce the concept of polymer based chemical delivery to multichannel capillary patterned cells. Here we demonstrate that UV polymerized hydrogel can be used as a miniature pipet to deliver picolitre chemical quantities to multichannel capillary patterned cells.
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Affiliation(s)
- Sung Hoon Lee
- School of Electrical Engineering and Computer Science, Seoul National University, Seoul, South Korea
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36
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Pompano RR, Liu W, Du W, Ismagilov RF. Microfluidics using spatially defined arrays of droplets in one, two, and three dimensions. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2011; 4:59-81. [PMID: 21370983 DOI: 10.1146/annurev.anchem.012809.102303] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Spatially defined arrays of droplets differ from bulk emulsions in that droplets in arrays can be indexed on the basis of one or more spatial variables to enable identification, monitoring, and addressability of individual droplets. Spatial indexing is critical in experiments with hundreds to millions of unique compartmentalized microscale processes--for example, in applications such as digital measurements of rare events in a large sample, high-throughput time-lapse studies of the contents of individual droplets, and controlled droplet-droplet interactions. This review describes approaches for spatially organizing and manipulating droplets in one-, two-, and three-dimensional structured arrays, including aspiration, laminar flow, droplet traps, the SlipChip, self-assembly, and optical or electrical fields. This review also presents techniques to analyze droplets in arrays and applications of spatially defined arrays, including time-lapse studies of chemical, enzymatic, and cellular processes, as well as further opportunities in chemical, biological, and engineering sciences, including perturbation/response experiments and personal and point-of-care diagnostics.
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Affiliation(s)
- Rebecca R Pompano
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
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37
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Sakakihara S, Araki S, Iino R, Noji H. A single-molecule enzymatic assay in a directly accessible femtoliter droplet array. LAB ON A CHIP 2010; 10:3355-62. [PMID: 21031171 DOI: 10.1039/c0lc00062k] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The enzyme assay in a femtoliter chamber array is a simple and efficient method for concentrating the reaction product; it greatly improves the detection sensitivity down to the single-molecule level. However, in previous methods, controlling the initiation and termination of the reaction in each chamber is difficult once enclosed. Furthermore, the recovery of the enzyme and product is also difficult. To overcome these drawbacks, we developed a femtoliter droplet array in which the individual droplets are fixed on the substrate and are directly accessible from outside. A hydrophilic-in-hydrophobic micropatterned surface was used for the preparation of the droplets. When the aqueous solution on the surface is exchanged with oil, the hydrophilic surface retains the aqueous solution, and more than 10(6) dome-shaped droplets that are usable for further assay can be prepared simultaneously. The curvature radius of the droplet obeys the Young-Laplace equation, and the volume can be precisely controlled by the micropipette, which applies pressure into the droplet. Changing the pressure makes the addition, collection, and exchange of the aqueous content for individual droplets possible. Using these advantages, we successfully measured the kinetic parameters of the single-molecule enzyme β-galactosidase and rotary motor protein F(1)-ATPase enclosed in a droplet.
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Affiliation(s)
- Shouichi Sakakihara
- Institute of Scientific and Industrial Research, Osaka University, Mihogaoka, 8-1, Ibaraki, Osaka 567-0047, Japan
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38
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Lee SH, Choi SE, Heinz AJ, Park W, Han S, Jung Y, Kwon S. Active guidance of 3D microstructures. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2010; 6:2668-2672. [PMID: 21064088 DOI: 10.1002/smll.201001248] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- Sung Hoon Lee
- School of Electrical Engineering and Computer Science, Seoul National University, San 56-1, Daehak-dong, Gwanak-gu, Seoul 151-744, South Korea
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39
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Duraiswamy S, Khan SA. Plasmonic nanoshell synthesis in microfluidic composite foams. NANO LETTERS 2010; 10:3757-63. [PMID: 20731386 DOI: 10.1021/nl102478q] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The availability of robust, scalable, and automated nanoparticle manufacturing processes is crucial for the viability of emerging nanotechnologies. Metallic nanoparticles of diverse shape and composition are commonly manufactured by solution-phase colloidal chemistry methods, where rapid reaction kinetics and physical processes such as mixing are inextricably coupled, and scale-up often poses insurmountable problems. Here we present the first continuous flow process to synthesize thin gold "nanoshells" and "nanoislands" on colloidal silica surfaces, which are nanoparticle motifs of considerable interest in plasmonics-based applications. We assemble an ordered, flowing composite foam lattice in a simple microfluidic device, where the lattice cells are alternately aqueous drops containing reagents for nanoparticle synthesis or gas bubbles. Microfluidic foam generation enables precisely controlled reagent dispensing and mixing, and the ordered foam structure facilitates compartmentalized nanoparticle growth. This is a general method for aqueous colloidal synthesis, enabling continuous, inherently digital, scalable, and automated production processes for plasmonic nanomaterials.
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Affiliation(s)
- Suhanya Duraiswamy
- Department of Chemical and Biomolecular Engineering, 4 Engineering Drive 4, E5-02-28, Singapore
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40
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Kazemi Oskooei SA, Sinton D. Partial wetting gas-liquid segmented flow microreactor. LAB ON A CHIP 2010; 10:1732-1734. [PMID: 20383398 DOI: 10.1039/c002754e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A microfluidic reactor strategy for reducing plug-to-plug transport in gas-liquid segmented flow microfluidic reactors is presented. The segmented flow is generated in a wetting portion of the chip that transitions downstream to a partially wetting reaction channel that serves to disconnect the liquid plugs. The resulting residence time distributions show little dependence on channel length, and over 60% narrowing in residence time distribution as compared to an otherwise similar reactor. This partial wetting strategy mitigates a central limitation (plug-to-plug dispersion) while preserving the many attractive features of gas-liquid segmented flow reactors.
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Affiliation(s)
- S Ali Kazemi Oskooei
- Department of Mechanical Engineering, University of Victoria, Victoria, BC, CanadaV8W 3P6
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41
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Kreutz JE, Shukhaev A, Du W, Druskin S, Daugulis O, Ismagilov RF. Evolution of catalysts directed by genetic algorithms in a plug-based microfluidic device tested with oxidation of methane by oxygen. J Am Chem Soc 2010; 132:3128-32. [PMID: 20148558 PMCID: PMC2861856 DOI: 10.1021/ja909853x] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This paper uses microfluidics to implement genetic algorithms (GA) to discover new homogeneous catalysts using the oxidation of methane by molecular oxygen as a model system. The parameters of the GA were the catalyst, a cocatalyst capable of using molecular oxygen as the terminal oxidant, and ligands that could tune the catalytic system. The GA required running hundreds of reactions to discover and optimize catalyst systems of high fitness, and microfluidics enabled these numerous reactions to be run in parallel. The small scale and volumes of microfluidics offer significant safety benefits. The microfluidic system included methods to form diverse arrays of plugs containing catalysts, introduce gaseous reagents at high pressure, run reactions in parallel, and detect catalyst activity using an in situ indicator system. Platinum(II) was identified as an active catalyst, and iron(II) and the polyoxometalate H(5)PMo(10)V(2)O(40) (POM-V2) were identified as active cocatalysts. The Pt/Fe system was further optimized and characterized using NMR experiments. After optimization, turnover numbers of approximately 50 were achieved with approximately equal production of methanol and formic acid. The Pt/Fe system demonstrated the compatibility of iron with the entire catalytic cycle. This approach of GA-guided evolution has the potential to accelerate discovery in catalysis and other areas where exploration of chemical space is essential, including optimization of materials for hydrogen storage and CO(2) capture and modifications.
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Affiliation(s)
- Jason E. Kreutz
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637
| | - Anton Shukhaev
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637
| | - Wenbin Du
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637
| | - Sasha Druskin
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637
| | - Olafs Daugulis
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003
| | - Rustem F. Ismagilov
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637
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42
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Choi JH, Lee SK, Lim JM, Yang SM, Yi GR. Designed pneumatic valve actuators for controlled droplet breakup and generation. LAB ON A CHIP 2010; 10:456-461. [PMID: 20126685 DOI: 10.1039/b915596a] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The dynamic breakup of emulsion droplets was demonstrated in double-layered microfluidic devices equipped with designed pneumatic actuators. Uniform emulsion droplets, produced by shearing at a T-junction, were broken into smaller droplets when they passed downstream through constrictions formed by a pneumatically actuated valve in the upper control layer. The valve-assisted droplet breakup was significantly affected by the shape and layout of the control valves on the emulsion flow channel. Interestingly, by actuating the pneumatic valve immediately above the T-junction, the sizes of the emulsion droplets were controlled precisely in a programmatic manner that produced arrays of uniform emulsion droplets in various sizes and dynamic patterns.
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Affiliation(s)
- Jae-Hoon Choi
- National Creative Research Initiative Center for Integrated Optofluidic Systems, Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 305-701, Republic of Korea
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43
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Wang J, Zhang J, Han J. Synthesis of crystals and particles by crystallization and polymerization in droplet-based microfluidic devices. ACTA ACUST UNITED AC 2010. [DOI: 10.1007/s11705-009-0292-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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44
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Wu N, Oakeshott J, Brown S, Easton C, Zhu Y. Microfluidic Droplet Technique for In Vitro Directed Evolution. Aust J Chem 2010. [DOI: 10.1071/ch10116] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Increasingly over the past two decades, biotechnologists have been exploiting various molecular technologies for high-throughput screening of genes and their protein products to isolate novel functionalities with a wide range of industrial applications. One particular technology now widely used for these purposes involves directed evolution, an artificial form of evolution in which genes and proteins are evolved towards new or improved functions by imposing intense selection pressures on libraries of mutant genes generated by molecular biology techniques and expressed in heterologous systems such as Escherichia coli. Most recently, the rapid development of droplet-based microfluidics has created the potential to dramatically increase the power of directed evolution by increasing the size of the libraries and the throughput of the screening by several orders of magnitude. Here, we review the methods for generating and controlling droplets in microfluidic systems, and their applications in directed evolution. We focus on the methodologies for cell-based assays, in vitro protein expression and DNA amplification, and the prospects for using such platforms for directed evolution in next-generation biotechnologies.
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45
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Duraiswamy S, Khan SA. Droplet-based microfluidic synthesis of anisotropic metal nanocrystals. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2009; 5:2828-34. [PMID: 19787681 DOI: 10.1002/smll.200901453] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
A droplet-based microfluidic method for the preparation of anisotropic gold nanocrystal dispersions is presented. Gold nanoparticle seeds and growth reagents are dispensed into monodisperse picoliter droplets within a microchannel. Confinement within small droplets prevents contact between the growing nanocrystals and the microchannel walls. The critical factors in translating macroscale flask-based methods to a flow-based microfluidic method are highlighted and approaches are demonstrated to flexibly fine tune nanoparticle shapes into three broad classes: spheres/spheroids, rods, and extended sharp-edged structures, thus varying the optical resonances in the visible-near-infrared (NIR) spectral range.
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Affiliation(s)
- Suhanya Duraiswamy
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, E5-02-28, 117576 Singapore
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Khan SA, Duraiswamy S. Microfluidic emulsions with dynamic compound drops. LAB ON A CHIP 2009; 9:1840-2. [PMID: 19532957 DOI: 10.1039/b904119b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We demonstrate a new class of microfluidic emulsion where the 'drops' of the emulsion are dynamic reversible bubble-drop pairs, with potential applications in microfluidic technology for chemical synthesis, molecular separations and screening.
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Affiliation(s)
- Saif A Khan
- Department of Chemical and Biomolecular Engineering, 4 Engineering Drive 4, E5-02-28, Singapore117576.
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Courtois F, Olguin LF, Whyte G, Theberge AB, Huck WTS, Hollfelder F, Abell C. Controlling the Retention of Small Molecules in Emulsion Microdroplets for Use in Cell-Based Assays. Anal Chem 2009; 81:3008-16. [DOI: 10.1021/ac802658n] [Citation(s) in RCA: 155] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Fabienne Courtois
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, U.K., and Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
| | - Luis F. Olguin
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, U.K., and Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
| | - Graeme Whyte
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, U.K., and Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
| | - Ashleigh B. Theberge
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, U.K., and Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
| | - Wilhelm T. S. Huck
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, U.K., and Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
| | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, U.K., and Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
| | - Chris Abell
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, U.K., and Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
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Surenjav E, Priest C, Herminghaus S, Seemann R. Manipulation of gel emulsions by variable microchannel geometry. LAB ON A CHIP 2009; 9:325-330. [PMID: 19107292 DOI: 10.1039/b808160c] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In this article we investigate the morphology and manipulation of monodisperse emulsions at high dispersed phase volume fractions (gel emulsions) in a microfluidic environment. Confined monodisperse gel emulsions self-organize into well-ordered droplet arrangements, which may be stable or metastable, depending on the geometry of the confining microchannel. Three arrangements are considered, in which the droplets are aligned in a single file, a two row, or a three row arrangement. We explore the potential for induced transitions between these distinct droplet arrangements as a tool for droplet-based microfluidic processing. Transitions are readily achieved by means of localized (geometrical) features in channel geometry, however the onset of the transition is strongly dependent on the subtleties of the microfluidic system, e.g. volume fraction, droplet size, and feature dimensions. The transitions can be achieved via fixed channel features or, when the continuous phase is a ferrofluid, by a virtual channel constriction created using a magnetic field.
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Affiliation(s)
- Enkhtuul Surenjav
- Max Planck Institute for Dynamics and Self-Organization, D-37073, Göttingen, Germany
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Hu TC, Korczyńska J, Smith DK, Brzozowski AM. High-molecular-weight polymers for protein crystallization: poly-gamma-glutamic acid-based precipitants. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2008; 64:957-63. [PMID: 18703844 PMCID: PMC2526455 DOI: 10.1107/s0907444908021616] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Accepted: 07/11/2008] [Indexed: 11/10/2022]
Abstract
Protein crystallization has been revolutionized by the introduction of high-throughput technologies, which have led to a speeding up of the process while simultaneously reducing the amount of protein sample necessary. Nonetheless, the chemistry dimension of protein crystallization has remained relatively undeveloped. Most crystallization screens are based on the same set of precipitants. To address this shortcoming, the development of new protein precipitants based on poly-gamma-glutamic acid (PGA) polymers with different molecular-weight ranges is reported here: PGA-LM (low molecular weight) of approximately 400 kDa and PGA-HM (high molecular weight) of >1,000 kDa. It is also demonstrated that protein precipitants can be expanded further to polymers with much higher molecular weight than those that are currently in use. Furthermore, the modification of PGA-like polymers by covalent attachments of glucosamine substantially improved their solubility without affecting their crystallization properties. Some preliminary PGA-based screens are presented here.
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Affiliation(s)
- Ting-Chou Hu
- Department of Chemistry, University of York, York YO10 5YW, England
| | - Justyna Korczyńska
- Department of Chemistry, University of York, York YO10 5YW, England
- Structural Biology Laboratory, University of York, York YO10 5YW, England
| | - David K. Smith
- Department of Chemistry, University of York, York YO10 5YW, England
| | - Andrzej Marek Brzozowski
- Department of Chemistry, University of York, York YO10 5YW, England
- Structural Biology Laboratory, University of York, York YO10 5YW, England
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Kline TR, Runyon MK, Pothiawala M, Ismagilov RF. ABO, D blood typing and subtyping using plug-based microfluidics. Anal Chem 2008; 80:6190-7. [PMID: 18646778 PMCID: PMC2592685 DOI: 10.1021/ac800485q] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A plug-based microfluidic approach was used to perform multiple agglutination assays in parallel without cross-contamination and using only microliter volumes of blood. To perform agglutination assays on-chip, a microfluidic device was designed to combine aqueous streams of antibody, buffer, and red blood cells (RBCs) to form droplets 30-40 nL in volume surrounded by a fluorinated carrier fluid. Using this approach, proof-of-concept ABO and D (Rh) blood typing and group A subtyping were successfully performed by screening against multiple antigens without cross-contamination. On-chip subtyping distinguished common A1 and A2 RBCs by using a lectin-based dilution assay. This flexible platform was extended to differentiate rare, weakly agglutinating RBCs of A subtypes by analyzing agglutination avidity as a function of shear rate. Quantitative analysis of changes in contrast within plugs revealed subtleties in agglutination kinetics and enabled characterization of agglutination of rare blood subtypes. Finally, this platform was used to detect bacteria, demonstrating the potential usefulness of this assay in detecting sepsis and the potential for applications in agglutination-based viral detection. The speed, control, and minimal sample consumption provided by this technology present an advance for point of care applications, blood typing of newborns, and general blood assays in small model organisms.
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Affiliation(s)
- Timothy R Kline
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA
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