1
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Gonçalves RC, Oliveira MB, Mano JF. Exploring the potential of all-aqueous immiscible systems for preparing complex biomaterials and cellular constructs. MATERIALS HORIZONS 2024; 11:4573-4599. [PMID: 39010747 DOI: 10.1039/d4mh00431k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
All-aqueous immiscible systems derived from liquid-liquid phase separation of incompatible hydrophilic agents such as polymers and salts have found increasing interest in the biomedical and tissue engineering fields in the last few years. The unique characteristics of aqueous interfaces, namely their low interfacial tension and elevated permeability, as well as the non-toxic environment and high water content of the immiscible phases, confer to these systems optimal qualities for the development of biomaterials such as hydrogels and soft membranes, as well as for the preparation of in vitro tissues derived from cellular assembly. Here, we overview the main properties of these systems and present a critical review of recent strategies that have been used for the development of biomaterials with increased levels of complexity using all-aqueous immiscible phases and interfaces, and their potential as cell-confining environments for micropatterning approaches and the bioengineering of cell-rich structures. Importantly, due to the relatively recent emergence of these areas, several key design considerations are presented, in order to guide researchers in the field. Finally, the main present challenges, future directions, and adaptability to develop advanced materials with increased biomimicry and new potential applications are briefly evaluated.
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Affiliation(s)
- Raquel C Gonçalves
- Department of Chemistry, CICECO - Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
| | - Mariana B Oliveira
- Department of Chemistry, CICECO - Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
| | - João F Mano
- Department of Chemistry, CICECO - Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
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2
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Honaker LW, Gao T, de Graaf KR, Bogaardt TV, Vink P, Stürzer T, Kociok‐Köhn G, Zuilhof H, Miloserdov FM, Deshpande S. 2D and 3D Self-Assembly of Fluorine-Free Pillar-[5]-Arenes and Perfluorinated Diacids at All-Aqueous Interfaces. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2401807. [PMID: 38790132 PMCID: PMC11304270 DOI: 10.1002/advs.202401807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Indexed: 05/26/2024]
Abstract
The interaction of perfluorinated molecules, also known as "forever chemicals" due to their pervasiveness, with their environment remains an important yet poorly understood topic. In this work, the self-assembly of perfluorinated molecules with multivalent hosts, pillar-[5]-arenes, is investigated. It is found that perfluoroalkyl diacids and pillar-[5]-arenes rapidly and strongly complex with each other at aqueous interfaces, forming solid interfacially templated films. Their complexation is shown to be driven primarily by fluorophilic aggregation and assisted by electrostatic interactions, as supported by the crystal structure of the complexes, and leads to the formation of quasi-2D phase-separated films. This self-assembly process can be further manipulated using aqueous two-phase system microdroplets, enabling the controlled formation of 3D micro-scaffolds.
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Affiliation(s)
- Lawrence W. Honaker
- Laboratory of Physical Chemistry and Soft MatterWageningen University & ResearchWageningen6708 WEThe Netherlands
| | - Tu‐Nan Gao
- Laboratory of Organic ChemistryWageningen University & ResearchWageningen6708 WEThe Netherlands
- Biobased Chemistry and TechnologyWageningen University & ResearchWageningen6708 WGThe Netherlands
| | - Kelsey R. de Graaf
- Laboratory of Physical Chemistry and Soft MatterWageningen University & ResearchWageningen6708 WEThe Netherlands
- Laboratory of Organic ChemistryWageningen University & ResearchWageningen6708 WEThe Netherlands
| | - Tessa V.M. Bogaardt
- Laboratory of Physical Chemistry and Soft MatterWageningen University & ResearchWageningen6708 WEThe Netherlands
| | - Pim Vink
- Laboratory of Physical Chemistry and Soft MatterWageningen University & ResearchWageningen6708 WEThe Netherlands
| | | | | | - Han Zuilhof
- Laboratory of Organic ChemistryWageningen University & ResearchWageningen6708 WEThe Netherlands
- School of Pharmaceutical Science and TechnologyTianjin UniversityTianjin300072P. R. China
- China–Australia Institute for Advanced Materials and ManufacturingJiaxing UniversityJiaxing314001P. R. China
| | - Fedor M. Miloserdov
- Laboratory of Organic ChemistryWageningen University & ResearchWageningen6708 WEThe Netherlands
| | - Siddharth Deshpande
- Laboratory of Physical Chemistry and Soft MatterWageningen University & ResearchWageningen6708 WEThe Netherlands
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3
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Ghasemzaie N, Jeyhani M, Joshi K, Lee WL, Tsai SSH. ATPSpin: A Single Microfluidic Platform that Produces Diversified ATPS-Alginate Microfibers. ACS Biomater Sci Eng 2024; 10:3896-3908. [PMID: 38748191 DOI: 10.1021/acsbiomaterials.4c00110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Microfluidic spinning is emerging as a useful technique in the fabrication of alginate fibers, enabling applications in drug screening, disease modeling, and disease diagnostics. In this paper, by capitalizing on the benefits of aqueous two-phase systems (ATPS) to produce diverse alginate fiber forms, we introduce an ATPS-Spinning platform (ATPSpin). This ATPS-enabled method efficiently circumvents the rapid clogging challenges inherent to traditional fiber production techniques by regulating the interaction between alginate and cross-linking agents like Ba2+ ions. By varying system parameters under the guidance of a regime map, our system produces several fiber forms─solid, hollow, and droplet-filled─consistently and reproducibly from a single device. We demonstrate that the resulting alginate fibers possess distinct features, including biocompatibility. We also encapsulate HEK293 cells in the microfibers as a proof-of-concept that this versatile microfluidic fiber generation platform may have utility in tissue engineering and regenerative medicine applications.
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Affiliation(s)
- Niloofar Ghasemzaie
- Biomedical Engineering Graduate Program, Toronto Metropolitan University, Toronto, Ontario, Canada M5B 2K3
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada M5B 1T8
- Institute for Biomedical Engineering, Science and Technology (iBEST), Toronto, Ontario, Canada M5B 1T8
| | - Morteza Jeyhani
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada M5B 1T8
- Department of Mechanical, Industrial, and Mechatronics Engineering, Toronto Metropolitan University, Toronto, Ontario, Canada M5B 2K3
- Institute for Biomedical Engineering, Science and Technology (iBEST), Toronto, Ontario, Canada M5B 1T8
| | - Kushal Joshi
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada M5B 1T8
- Department of Mechanical, Industrial, and Mechatronics Engineering, Toronto Metropolitan University, Toronto, Ontario, Canada M5B 2K3
- Institute for Biomedical Engineering, Science and Technology (iBEST), Toronto, Ontario, Canada M5B 1T8
| | - Warren L Lee
- Biomedical Engineering Graduate Program, Toronto Metropolitan University, Toronto, Ontario, Canada M5B 2K3
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada M5B 1T8
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada M5S 1A1
- Institute for Biomedical Engineering, Science and Technology (iBEST), Toronto, Ontario, Canada M5B 1T8
| | - Scott S H Tsai
- Biomedical Engineering Graduate Program, Toronto Metropolitan University, Toronto, Ontario, Canada M5B 2K3
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada M5B 1T8
- Department of Mechanical, Industrial, and Mechatronics Engineering, Toronto Metropolitan University, Toronto, Ontario, Canada M5B 2K3
- Institute for Biomedical Engineering, Science and Technology (iBEST), Toronto, Ontario, Canada M5B 1T8
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4
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Jegatheeswaran S, Tan JH, Fraser AG, Hwang DK. Encapsulation of Caenorhabditis elegans in Water-in-Water Microdroplets to Study the Worm Viability: Alternative Avenue to Manipulate Microdroplet Environment. ACS APPLIED MATERIALS & INTERFACES 2023; 15:59037-59043. [PMID: 38063021 DOI: 10.1021/acsami.3c14176] [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: 12/22/2023]
Abstract
Due to the great biocompatibility of the aqueous two phase system (ATPS), biological cells have been widely encapsulated in ATPS microdroplets (diameter < 50 μm). However, the immobilization of relatively large multicellular organisms such as Caenorhabditis elegans in ATPS droplets remains challenging as the spontaneous generation of droplets greater than 200 μm is difficult without external perturbations. In this study, we utilize a microneedle-assisted coflow microfludic channel to passively form ATPS microdroplets larger than 200 μm and successfully entrap C. elegans in the microdroplets. We monitor the worm viability and its temporal stroke frequency up to 6 h. We study the effects of dextran (DEX)-to-polyethylene glycol (PEG) flow ratios and worm concentration on the droplet diameter, worm encapsulation efficiency, and the number of droplets containing individual worms. Larger ATPS microdroplets (>200 μm) form in the ranges of capillary number (Ca) between 0.020 to 0.20 and Weber number (We) between 10-5 and 10-3. An ATPS with the encapsulation ability and biocompatibility can offer an alternative immobilization tool for multicellular organisms to existing platforms such as water/oil droplets.
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Affiliation(s)
- Sinthuran Jegatheeswaran
- Department of Chemical Engineering, Toronto Metropolitan University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, 30 Bond Street, Toronto, Ontario M5B 1W8, Canada
- Institute for Biomedical Engineering, Science and Technology (iBEST), A Partnership Between Toronto Metropolitan University and St. Michael's Hospital, 30 Bond Street, Toronto, Ontario M5B 1W8, Canada
| | - June H Tan
- The Donnelly Centre, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Andrew G Fraser
- The Donnelly Centre, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Dae Kun Hwang
- Department of Chemical Engineering, Toronto Metropolitan University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, 30 Bond Street, Toronto, Ontario M5B 1W8, Canada
- Institute for Biomedical Engineering, Science and Technology (iBEST), A Partnership Between Toronto Metropolitan University and St. Michael's Hospital, 30 Bond Street, Toronto, Ontario M5B 1W8, Canada
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5
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Abbasi N, Nunes JK, Pan Z, Dethe T, Shum HC, Košmrlj A, Stone HA. Flows of a nonequilibrated aqueous two-phase system in a microchannel. SOFT MATTER 2023; 19:3551-3561. [PMID: 37144458 DOI: 10.1039/d3sm00233k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Liquid-liquid phase separation is a rich and dynamic process, which recently has gained new interest, especially in biology and for material synthesis. In this work, we experimentally show that co-flow of a nonequilibrated aqueous two-phase system within a planar flow-focusing microfluidic device results in a three-dimensional flow, as the two nonequilibrated solutions move downstream along the length of the microchannel. After the system reaches steady-state, invasion fronts from the outer stream are formed along the top and bottom walls of the microfluidic device. The invasion fronts advance towards the center of the channel, until they merge. We first show by tuning the concentration of polymer species within the system that the formation of these fronts is due to liquid-liquid phase separation. Moreover, the rate of invasion from the outer stream increases with increasing polymer concentrations in the streams. We hypothesize the invasion front formation and growth is driven by Marangoni flow induced by the polymer concentration gradient along the width of the channel, as the system is undergoing phase separation. In addition, we show how at various downstream positions the system reaches its steady-state configuration once the two fluid streams flow side-by-side in the channel.
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Affiliation(s)
- Niki Abbasi
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA.
| | - Janine K Nunes
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA.
| | - Zehao Pan
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA.
| | - Tejas Dethe
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA.
| | - Ho Cheung Shum
- Department of Mechanical Engineering, University of Hong Kong, Hong Kong, China
| | - Andrej Košmrlj
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA.
- Princeton Materials Institute, Princeton University, Princeton, NJ, USA
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA.
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6
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Udono H, Gong J, Sato Y, Takinoue M. DNA Droplets: Intelligent, Dynamic Fluid. Adv Biol (Weinh) 2023; 7:e2200180. [PMID: 36470673 DOI: 10.1002/adbi.202200180] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/14/2022] [Indexed: 12/12/2022]
Abstract
Breathtaking advances in DNA nanotechnology have established DNA as a promising biomaterial for the fabrication of programmable higher-order nano/microstructures. In the context of developing artificial cells and tissues, DNA droplets have emerged as a powerful platform for creating intelligent, dynamic cell-like machinery. DNA droplets are a microscale membrane-free coacervate of DNA formed through phase separation. This new type of DNA system couples dynamic fluid-like property with long-established DNA programmability. This hybrid nature offers an advantageous route to facile and robust control over the structures, functions, and behaviors of DNA droplets. This review begins by describing programmable DNA condensation, commenting on the physical properties and fabrication strategies of DNA hydrogels and droplets. By presenting an overview of the development pathways leading to DNA droplets, it is shown that DNA technology has evolved from static, rigid systems to soft, dynamic systems. Next, the basic characteristics of DNA droplets are described as intelligent, dynamic fluid by showcasing the latest examples highlighting their distinctive features related to sequence-specific interactions and programmable mechanical properties. Finally, this review discusses the potential and challenges of numerical modeling able to connect a robust link between individual sequences and macroscopic mechanical properties of DNA droplets.
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Affiliation(s)
- Hirotake Udono
- Department of Computer Science, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8502, Japan
| | - Jing Gong
- Department of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8502, Japan
| | - Yusuke Sato
- Department of Intelligent and Control Systems, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502, Japan
| | - Masahiro Takinoue
- Department of Computer Science, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8502, Japan
- Department of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8502, Japan
- Living Systems Materialogy (LiSM) Research Group, International Research Frontiers Initiative (IRFI), Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8502, Japan
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7
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Kieda J, Appak-Baskoy S, Jeyhani M, Navi M, Chan KWY, Tsai SSH. Microfluidically-generated Encapsulated Spheroids (μ-GELS): An All-Aqueous Droplet Microfluidics Platform for Multicellular Spheroids Generation. ACS Biomater Sci Eng 2023; 9:1043-1052. [PMID: 36626575 DOI: 10.1021/acsbiomaterials.2c00963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Spheroids are three-dimensional clusters of cells that serve as in vitro tumor models to recapitulate in vivo morphology. A limitation of many existing on-chip platforms for spheroid formation is the use of cytotoxic organic solvents as the continuous phase in droplet generation processes. All-aqueous methods do not contain cytotoxic organic solvents but have so far been unable to achieve complete hydrogel gelation on chip. Here, we describe an enhanced droplet microfluidic platform that achieves on-chip gelation of all-aqueous hydrogel multicellular spheroids (MCSs). Specifically, we generate dextran-alginate droplets containing MCF-7 breast cancer cells, surrounded by polyethylene glycol, at a flow-focusing junction. Droplets then travel to a second flow-focusing junction where they interact with calcium chloride and gel on chip to form hydrogel MCSs. On-chip gelation of the MCSs is possible here because of an embedded capillary at the second junction that delays the droplet gelation, which prevents channel clogging problems that would otherwise exist. In drug-free experiments, we demonstrate that MCSs remain viable for 6 days. We also confirm the applicability of this system for cancer drug testing by observing that dose-dependent cell death is achievable using doxorubicin.
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Affiliation(s)
- Jennifer Kieda
- Graduate Program in Biomedical Engineering, Toronto Metropolitan University, TorontoM5B 2K3, Canada.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, TorontoM5B 2K3, Canada.,Institute for Biomedical Engineering, Science, and Technology (iBEST) - A partnership between Toronto Metropolitan University and St. Michael's Hospital, TorontoM5B 1W8, Canada
| | - Sila Appak-Baskoy
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, TorontoM5B 2K3, Canada.,Institute for Biomedical Engineering, Science, and Technology (iBEST) - A partnership between Toronto Metropolitan University and St. Michael's Hospital, TorontoM5B 1W8, Canada.,Department of Chemistry and Biology, Toronto Metropolitan University, TorontoM5B 2K3, Canada
| | - Morteza Jeyhani
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, TorontoM5B 2K3, Canada.,Institute for Biomedical Engineering, Science, and Technology (iBEST) - A partnership between Toronto Metropolitan University and St. Michael's Hospital, TorontoM5B 1W8, Canada.,Department of Mechanical and Industrial Engineering, Toronto Metropolitan University, TorontoM5B 2K3, Canada
| | - Maryam Navi
- Graduate Program in Biomedical Engineering, Toronto Metropolitan University, TorontoM5B 2K3, Canada.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, TorontoM5B 2K3, Canada.,Institute for Biomedical Engineering, Science, and Technology (iBEST) - A partnership between Toronto Metropolitan University and St. Michael's Hospital, TorontoM5B 1W8, Canada
| | - Katherine W Y Chan
- Graduate Program in Biomedical Engineering, Toronto Metropolitan University, TorontoM5B 2K3, Canada.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, TorontoM5B 2K3, Canada.,Institute for Biomedical Engineering, Science, and Technology (iBEST) - A partnership between Toronto Metropolitan University and St. Michael's Hospital, TorontoM5B 1W8, Canada
| | - Scott S H Tsai
- Graduate Program in Biomedical Engineering, Toronto Metropolitan University, TorontoM5B 2K3, Canada.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, TorontoM5B 2K3, Canada.,Institute for Biomedical Engineering, Science, and Technology (iBEST) - A partnership between Toronto Metropolitan University and St. Michael's Hospital, TorontoM5B 1W8, Canada.,Department of Mechanical and Industrial Engineering, Toronto Metropolitan University, TorontoM5B 2K3, Canada
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8
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Jeyhani M, Navi M, Chan KWY, Kieda J, Tsai SSH. Water-in-water droplet microfluidics: A design manual. BIOMICROFLUIDICS 2022; 16:061503. [PMID: 36406338 PMCID: PMC9674389 DOI: 10.1063/5.0119316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
Droplet microfluidics is utilized in a wide range of applications in biomedicine and biology. Applications include rapid biochemical analysis, materials generation, biochemical assays, and point-of-care medicine. The integration of aqueous two-phase systems (ATPSs) into droplet microfluidic platforms has potential utility in oil-free biological and biomedical applications, namely, reducing cytotoxicity and preserving the native form and function of costly biomolecular reagents. In this review, we present a design manual for the chemist, biologist, and engineer to design experiments in the context of their biological applications using all-in-water droplet microfluidic systems. We describe the studies achievable using these systems and the corresponding fabrication and stabilization methods. With this information, readers may apply the fundamental principles and recent advancements in ATPS droplet microfluidics to their research. Finally, we propose a development roadmap of opportunities to utilize ATPS droplet microfluidics in applications that remain underexplored.
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9
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Aqueous two-phase emulsions toward biologically relevant applications. TRENDS IN CHEMISTRY 2022. [DOI: 10.1016/j.trechm.2022.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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10
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Daradmare S, Lee CS. Recent progress in the synthesis of all-aqueous two-phase droplets using microfluidic approaches. Colloids Surf B Biointerfaces 2022; 219:112795. [PMID: 36049253 DOI: 10.1016/j.colsurfb.2022.112795] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 08/10/2022] [Accepted: 08/21/2022] [Indexed: 12/21/2022]
Abstract
An aqueous two-phase system (ATPS) is a system with liquid-liquid phase separation and shows great potential for the extraction, separation, purification, and enrichment of proteins, membranes, viruses, enzymes, nucleic acids, and other biomolecules because of its simplicity, biocompatibility, and wide applicability [1-4]. The clear aqueous-aqueous interface of ATPSs is highly advantageous for their implementation, therefore making ATPSs a green alternative approach to replace conventional emulsion systems, such as water-in-oil droplets. All aqueous emulsions (water-in-water, w-in-w) hold great promise in the biomedical field as glucose sensors [5] and promising carriers for the encapsulation and release of various biomolecules and nonbiomolecules [6-10]. However, the ultralow interfacial tension between the two phases is a hurdle in generating w-in-w emulsion droplets. In the past, bulk emulsification and electrospray techniques were employed for the generation of w-in-w emulsion droplets and the fabrication of microparticles and microcapsules in the later stage. Bulk emulsification is a simple and low-cost technique; however, it generates polydisperse w-in-w emulsion droplets. Another technique, electrospray, involves easy experimental setups that can generate monodisperse but nonspherical w-in-w emulsion droplets. In comparison, microfluidic platforms provide monodisperse w-in-w emulsion droplets with spherical shapes, deal with the small volumes of solutions and short reaction times and achieve portability and versatility in their design through rapid prototyping. Owing to several advantages, microfluidic approaches have recently been introduced. To date, several different strategies have been explored to generate w-in-w emulsions and multiple w-in-w emulsions and to fabricate microparticles and microcapsules using conventional microfluidic devices. Although a few review articles on ATPSs emulsions have been published in the past, to date, few reviews have exclusively focused on the evolution of microfluidic-based ATPS droplets. The present review begins with a brief discussion of the history of ATPSs and their fundamentals, which is followed by an account chronicling the integration of microfluidic devices with ATPSs to generate w-in-w emulsion droplets. Furthermore, the stabilization strategies of w-in-w emulsion droplets and microfluidic fabrication of microparticles and microcapsules for modern applications, such as biomolecule encapsulation and spheroid construction, are discussed in detail in this review. We believe that the present review will provide useful information to not only new entrants in the microfluidic community wanting to appreciate the findings of the field but also existing researchers wanting to keep themselves updated on progress in the field.
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Affiliation(s)
- Sneha Daradmare
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Republic of Korea
| | - Chang-Soo Lee
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Republic of Korea.
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11
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Spongy all-in-liquid materials by in-situ formation of emulsions at oil-water interfaces. Nat Commun 2022; 13:4162. [PMID: 35851272 PMCID: PMC9293904 DOI: 10.1038/s41467-022-31644-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 06/23/2022] [Indexed: 11/17/2022] Open
Abstract
Printing a structured network of functionalized droplets in a liquid medium enables engineering collectives of living cells for functional purposes and promises enormous applications in processes ranging from energy storage to tissue engineering. Current approaches are limited to drop-by-drop printing or face limitations in reproducing the sophisticated internal features of a structured material and its interactions with the surrounding media. Here, we report a simple approach for creating stable liquid filaments of silica nanoparticle dispersions and use them as inks to print all-in-liquid materials that consist of a network of droplets. Silica nanoparticles stabilize liquid filaments at Weber numbers two orders of magnitude smaller than previously reported in liquid-liquid systems by rapidly producing a concentrated emulsion zone at the oil-water interface. We experimentally demonstrate the printed aqueous phase is emulsified in-situ; consequently, a 3D structure is achieved with flexible walls consisting of layered emulsions. The tube-like printed features have a spongy texture resembling miniaturized versions of “tube sponges” found in the oceans. A scaling analysis based on the interplay between hydrodynamics and emulsification kinetics reveals that filaments are formed when emulsions are generated and remain at the interface during the printing period. Stabilized filaments are utilized for printing liquid-based fluidic channels. All-in-liquid printing promises applications from energy storage to drug delivery and tissue engineering. Here, authors present the in-situ generation of layered emulsion in a fraction of a second at the oil-water interface forming 3D tube-like structures in a liquid medium.
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12
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Zhou C, Zhu P, Tian Y, Shi R, Wang L. Progress in all-aqueous droplets generation with microfluidics: Mechanisms of formation and stability improvements. BIOPHYSICS REVIEWS 2022; 3:021301. [PMID: 38505416 PMCID: PMC10914135 DOI: 10.1063/5.0054201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 01/27/2022] [Indexed: 03/21/2024]
Abstract
All-aqueous systems have attracted intensive attention as a promising platform for applications in cell separation, protein partitioning, and DNA extraction, due to their selective separation capability, rapid mass transfer, and good biocompatibility. Reliable generation of all-aqueous droplets with accurate control over their size and size distribution is vital to meet the increasingly growing demands in emulsion-based applications. However, the ultra-low interfacial tension and large effective interfacial thickness of the water-water interface pose challenges for the generation and stabilization of uniform all-aqueous droplets, respectively. Microfluidics technology has emerged as a versatile platform for the precision generation of all-aqueous droplets with improved stability. This review aims to systematize the controllable generation of all-aqueous droplets and summarize various strategies to improve their stability with microfluidics. We first provide a comprehensive review on the recent progress of all-aqueous droplets generation with microfluidics by detailing the properties of all-aqueous systems, mechanisms of droplet formation, active and passive methods for droplet generation, and the property of droplets. We then review the various strategies used to improve the stability of all-aqueous droplets and discuss the fabrication of biomaterials using all-aqueous droplets as liquid templates. We envision that this review will benefit the future development of all-aqueous droplet generation and its applications in developing biomaterials, which will be useful for researchers working in the field of all-aqueous systems and those who are new and interested in the field.
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Affiliation(s)
| | - Pingan Zhu
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, China
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13
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W/W droplet-based microfluidic interfacial catalysis of xylanase-polymer conjugates for xylooligosaccharides production. Chem Eng Sci 2022. [DOI: 10.1016/j.ces.2021.117110] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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14
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Zhang J, Ling SD, Chen A, Chen Z, Ma W, Xu J. The liquid‐liquid flow dynamics and droplet formation in a modified step T‐junction Microchannel. AIChE J 2022. [DOI: 10.1002/aic.17611] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jingwei Zhang
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering Tsinghua University Beijing China
| | - Si Da Ling
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering Tsinghua University Beijing China
| | - An Chen
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering Tsinghua University Beijing China
| | - Zhuo Chen
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering Tsinghua University Beijing China
| | - Wenjun Ma
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering Tsinghua University Beijing China
| | - Jianhong Xu
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering Tsinghua University Beijing China
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15
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Hemachandran E, Hoque SZ, Laurell T, Sen AK. Reversible Stream Drop Transition in a Microfluidic Coflow System via On Demand Exposure to Acoustic Standing Waves. PHYSICAL REVIEW LETTERS 2021; 127:134501. [PMID: 34623851 DOI: 10.1103/physrevlett.127.134501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 07/16/2021] [Accepted: 08/18/2021] [Indexed: 06/13/2023]
Abstract
Transition between stream and droplet regimes in a coflow is typically achieved by adjusting the capillary numbers (Ca) of the phases. Remarkably, we experimentally evidence a reversible transition between the two regimes by controlling exposure of the system to acoustic standing waves, with Ca fixed. By satisfying the ratio of acoustic radiation force to the interfacial tension force, Ca_{ac}>1, experiments reveal a reversible stream drop transition for Ca<1, and stream relocation for Ca≥1. We explain the phenomenon in terms of the pinching, advection, and relocation timescales and a transition between convective and absolute instability from a linear stability analysis [P. Guillot et al., Phys. Rev. Lett. 99, 104502 (2007)PRLTAO0031-900710.1103/PhysRevLett.99.104502].
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Affiliation(s)
- E Hemachandran
- Fluid Systems Lab, Department of Mechanical Engineering, Indian Institute of Technology Madras, 600036 Chennai, India
| | - S Z Hoque
- Fluid Systems Lab, Department of Mechanical Engineering, Indian Institute of Technology Madras, 600036 Chennai, India
| | - T Laurell
- Division of Nanobiotechnology, Department of Biomedical Engineering, Lund University, 22363 Lund, Sweden
| | - A K Sen
- Fluid Systems Lab, Department of Mechanical Engineering, Indian Institute of Technology Madras, 600036 Chennai, India
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16
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Liquid Crystalline Microdroplets of Graphene Oxide via Microfluidics. CHINESE JOURNAL OF POLYMER SCIENCE 2021. [DOI: 10.1007/s10118-021-2619-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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17
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Gebhard F, Hartmann J, Hardt S. Interaction of proteins with phase boundaries in aqueous two-phase systems under electric fields. SOFT MATTER 2021; 17:3929-3936. [PMID: 33720237 DOI: 10.1039/d0sm01921f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The electric-field driven transport of proteins across the liquid-liquid interface in an aqueous two-phase system (ATPS) is studied in a microfluidic device using fluorescence microscopy. An ATPS containing polyethylene glycol (PEG) and dextran is employed, and bovine serum albumin (BSA) and bovine γ-globulins (BγG) are considered as model proteins. It is shown that both proteins, initially in the dextran-rich phase, accumulate at the liquid-liquid interface, preferably close to the three-phase contact line between the two liquid phases and the microchannel wall. It is in these regions where the proteins penetrate into the PEG-rich phase. The transport resistance of the liquid-liquid interface is higher for BγG than for BSA, such that a much larger molar flux of BSA into the PEG phase is observed. This opens up the opportunity of separating different protein species by utilizing differences in the transport resistance at the interface. A mathematical model is developed, accounting for adsorption and desorption processes at the liquid-liquid interface. The underlying theoretical concept is that of an electrostatic potential minimum formed by superposing the applied electric field and the field due to the Donnan potential at the interface. A fit of the model parameters to the experimental data results in good agreement between theory and experiments, thereby corroborating the underlying picture.
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Affiliation(s)
- Florian Gebhard
- Technische Universität Darmstadt, Fachbereich Maschinenbau, Alarich-Weiss-Str. 10, 64287 Darmstadt, Germany.
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18
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Song Q, Chao Y, Zhang Y, Shum HC. Controlled Formation of All-Aqueous Janus Droplets by Liquid-Liquid Phase Separation of an Aqueous Three-Phase System. J Phys Chem B 2021; 125:562-570. [PMID: 33416329 DOI: 10.1021/acs.jpcb.0c09884] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Janus droplets have been demonstrated in a wide range of applications, ranging from drug delivery, to biomedical imaging, to bacterial detection. However, existing fabrication strategies often involve nonaqueous solvents, such as organic solvent or oil, which largely limits their use in fields that require a high degree of biocompatibility. Here, we present a method to achieve all-aqueous Janus droplets by liquid-liquid phase separation of an aqueous three-phase system (A3PS). An aqueous droplet containing two initially miscible polymers is first injected into an aqueous solution of another concentrated polymer, and then it spontaneously phase-separates into a Janus droplet due to the diffusive mass exchange between the drop and bulk phases during equilibration. To achieve continuous generation of the Janus droplets, the A3PS is further integrated with microfluidics and electrospray. The size and shape of the phase-separated Janus droplets can be easily controlled by tuning the operation parameters, such as the flow rate and/or the initial composition of the drop phases. Dumbbell-shaped and snowman-shaped Janus droplets with average sizes between 100 and 400 μm can be generated by both coflow microfluidics and electrospray. In particular, the phase-separated Janus droplets can simultaneously load two different liposomes into each compartment, which are promising carriers for combination drugs. The obtained Janus droplets are superior templates for biocompatible materials, which can serve as building blocks such as high-order droplet patterns for constructing advanced biomaterials.
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Affiliation(s)
- Qingchun Song
- Department of Mechanical Engineering, Faculty of Engineering, The University of Hong Kong, Hong Kong (SAR), China
| | - Youchuang Chao
- Department of Mechanical Engineering, Faculty of Engineering, The University of Hong Kong, Hong Kong (SAR), China
| | - Yage Zhang
- Department of Mechanical Engineering, Faculty of Engineering, The University of Hong Kong, Hong Kong (SAR), China
| | - Ho Cheung Shum
- Department of Mechanical Engineering, Faculty of Engineering, The University of Hong Kong, Hong Kong (SAR), China
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19
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Tan S, Gao C, Liu H, Ye B, Sun D. Research of double emulsion formation and shell-thickness influence factors in a novel six-way junction microfluidic device. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.124917] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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20
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Navi M, Kieda J, Tsai SSH. Magnetic polyelectrolyte microcapsules via water-in-water droplet microfluidics. LAB ON A CHIP 2020; 20:2851-2860. [PMID: 32555881 DOI: 10.1039/d0lc00387e] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Polyelectrolyte microcapsules (PEMCs) have biocompatible microcompartments. Therefore, PEMCs are useful for applications in cosmetics, food, pharmaceutics, and other industries. The fabrication of PEMCs often involves the use of harsh chemicals or cytotoxic organic phases that make biomedical applications of the microcapsules challenging. In this report, we present an all-aqueous droplet microfluidics platform for the generation of magnetic PEMCs. In the platform, we use an aqueous-two-phase system (ATPS) of polyethylene glycol (PEG) and dextran (Dex), to generate water-in-water droplets, which are magnetically functionalized with ferrofluid. Strong polyelectrolytes (PEs) with opposite charges are used in each ATPS phase. We make emulsion templates of magnetic Dex, containing the polycations, in a continuous phase of PEG. We then apply a magnetic field to move the magnetic droplets to a second PEG phase, which contains the polyanions. By careful tuning of the fluxes of the two PEs in their respective phases, we trigger the formation of a shell at the droplet interface. Owing to the presence of the ferrofluid, the resulting microcapsules are magnetically responsive. We show that the magnetic PEMCs are capable of passive release of large pseudo-drugs as well as triggered release using external stimuli such as osmotic shock and pH change. We expect that magnetic PEMCs from this biocompatible all-aqueous platform will find utility in the fabrication of functionalized drug carriers for targeted drug delivery.
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Affiliation(s)
- Maryam Navi
- Graduate Program in Biomedical Engineering, Ryerson University, Toronto M5B 2K3, Canada.
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21
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Yang CG, Cheng L, Ye WQ, Zheng DH, Xu ZR. Preparation of encoded bar-like core-shell microparticles on a microfluidic chip. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2019.124373] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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22
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Navi M, Abbasi N, Salari A, Tsai SSH. Magnetic water-in-water droplet microfluidics: Systematic experiments and scaling mathematical analysis. BIOMICROFLUIDICS 2020; 14:024101. [PMID: 32161632 PMCID: PMC7056455 DOI: 10.1063/1.5144137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 02/23/2020] [Indexed: 05/30/2023]
Abstract
A major barrier to the clinical utilization of microfluidically generated water-in-oil droplets is the cumbersome washing steps required to remove the non-biocompatible organic oil phase from the droplets. In this paper, we report an on-chip magnetic water-in-water droplet generation and manipulation platform using a biocompatible aqueous two-phase system of a polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer (PEG-PPG-PEG) and dextran (DEX), eliminating the need for subsequent washing steps. By careful selection of a ferrofluid that shows an affinity toward the DEX phase (the dispersed phase in our microfluidic device), we generate magnetic DEX droplets in a non-magnetic continuous phase of PEG-PPG-PEG. We apply an external magnetic field to manipulate the droplets and sort them into different outlets. We also perform scaling analysis to model the droplet deflection and find that the experimental data show good agreement with the model. We expect that this type of all-biocompatible magnetic droplet microfluidic system will find utility in biomedical applications, such as long-term single cell analysis. In addition, the model can be used for designing experimental parameters to achieve a desired droplet trajectory.
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23
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Guerrero J, Chang YW, Fragkopoulos AA, Fernandez-Nieves A. Capillary-Based Microfluidics-Coflow, Flow-Focusing, Electro-Coflow, Drops, Jets, and Instabilities. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1904344. [PMID: 31663270 DOI: 10.1002/smll.201904344] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 09/13/2019] [Indexed: 06/10/2023]
Abstract
Capillary-based microfluidics is a great technique to produce monodisperse and complex emulsions and particulate suspensions. In this review, the current understanding of drop and jet formation in capillary-based microfluidic devices for two primary flow configurations, coflow and flow-focusing is summarized. The experimental and theoretical description of fluid instabilities is discussed and conditions for controlled drop breakup in different modes of drop generation are provided. Current challenges in drop breakup with low interfacial tension systems and recent progress in overcoming drop size limitations using electro-coflow are addressed. In each scenario, the physical mechanisms for drop breakup are revisited, and simple scaling arguments proposed in the literature are introduced.
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Affiliation(s)
- Josefa Guerrero
- Department of Chemistry and Physics, Augusta University, Augusta, GA, 30912, USA
| | - Ya-Wen Chang
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - Alexandros A Fragkopoulos
- Department of Dynamics of Complex Fluids, Max Planck Institute for Dynamics and Self-Organization, 37077, Göttingen, Germany
| | - Alberto Fernandez-Nieves
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Department of Condensed Matter Physics, University of Barcelona, 08028, Barcelona, Spain
- ICREA-Institució Caalana de Recerca i Estudis Avançats, 08010, Barcelona, Spain
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24
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Dincau B, Dressaire E, Sauret A. Pulsatile Flow in Microfluidic Systems. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1904032. [PMID: 31657131 DOI: 10.1002/smll.201904032] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/17/2019] [Indexed: 06/10/2023]
Abstract
This review describes the current knowledge and applications of pulsatile flow in microfluidic systems. Elements of fluid dynamics at low Reynolds number are first described in the context of pulsatile flow. Then the practical applications in microfluidic processes are presented: the methods to generate a pulsatile flow, the generation of emulsion droplets through harmonic flow rate perturbation, the applications in mixing and particle separation, and the benefits of pulsatile flow for clog mitigation. The second part of the review is devoted to pulsatile flow in biological applications. Pulsatile flows can be used for mimicking physiological systems, to alter or enhance cell cultures, and for bioassay automation. Pulsatile flows offer unique advantages over a steady flow, especially in microfluidic systems, but also require some new physical insights and more rigorous investigation to fully benefit future applications.
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Affiliation(s)
- Brian Dincau
- Department of Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Emilie Dressaire
- Department of Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Alban Sauret
- Department of Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
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25
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Chao Y, Shum HC. Emerging aqueous two-phase systems: from fundamentals of interfaces to biomedical applications. Chem Soc Rev 2020; 49:114-142. [DOI: 10.1039/c9cs00466a] [Citation(s) in RCA: 138] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This review summarizes recent advances of aqueous two-phase systems (ATPSs), particularly their interfaces, with a focus on biomedical applications.
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Affiliation(s)
- Youchuang Chao
- Department of Mechanical Engineering
- The University of Hong Kong
- China
| | - Ho Cheung Shum
- Department of Mechanical Engineering
- The University of Hong Kong
- China
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26
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Cabezas MG, Herrada MA, Montanero JM. Stability of a jet moving in a rectangular microchannel. Phys Rev E 2019; 100:053104. [PMID: 31870010 DOI: 10.1103/physreve.100.053104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Indexed: 06/10/2023]
Abstract
We study numerically the basic flow and linear stability of a capillary jet confined in a rectangular microchannel. We consider both the case where the interface does not touch the solid surfaces and that in which the jet adheres to them with a contact angle slightly smaller than 180^{∘}. Given an arbitrary set of values of the governing parameters, the fully developed (parallel) two-dimensional basic flow is calculated and then the growth rate of the dominant perturbation mode is determined as a function of the wave number. The flow is linearly stable if that growth rate is negative for all the wave numbers considered. We show that when the coflowing stream viscosity is sufficiently small in terms of that of the jet, there is an interval of the flow rate ratio Q for which the jet adheres to the walls or not depending on whether the flow is established by decreasing or increasing the value of Q. When the distance between the interface and the channel wall is of the order of the jet radius, the jet is unconditionally unstable. However, for sufficiently small interface-to-wall distances, the viscous stress can dominate the capillary pressure and fully stabilize the flow. Our results suggest that the capillary modes are suppressed and the flow becomes stable when the jet adheres to the channel walls. The combination of the above results indicates that, under certain parametric conditions, stable or unstable jets can be formed depending on whether the experimenter sets the flow rate ratio by decreasing or increasing progressively the jet flow rate while keeping constant that of the outer stream. Our theoretical predictions for the stablity of a coflow in a rectangular channel are consistent with previous experimental results [Humphry et al., Phys. Rev. E 79, 056310 (2009)PLEEE81539-375510.1103/PhysRevE.79.056310].
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Affiliation(s)
- M G Cabezas
- Departmento de Ingeniería Mecánica, Energética y de los Materiales and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, Avda. de Elvas s/n, E-06071 Badajoz, Spain
| | - M A Herrada
- Escuela Técnica Superior de Ingenieros, Universidad de Sevilla, Avda. de los Descubrimientos s/n, E-41092-Sevilla, Spain
| | - José M Montanero
- Departmento de Ingeniería Mecánica, Energética y de los Materiales and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, Avda. de Elvas s/n, E-06071 Badajoz, Spain
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27
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Mastiani M, Firoozi N, Petrozzi N, Seo S, Kim M. Polymer-Salt Aqueous Two-Phase System (ATPS) Micro-Droplets for Cell Encapsulation. Sci Rep 2019; 9:15561. [PMID: 31664112 PMCID: PMC6820865 DOI: 10.1038/s41598-019-51958-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 10/10/2019] [Indexed: 02/07/2023] Open
Abstract
Biosample encapsulation is a critical step in a wide range of biomedical and bioengineering applications. Aqueous two-phase system (ATPS) droplets have been recently introduced and showed a great promise to the biological separation and encapsulation due to their excellent biocompatibility. This study shows for the first time the passive generation of salt-based ATPS microdroplets and their biocompatibility test. We used two ATPS including polymer/polymer (polyethylene glycol (PEG)/dextran (DEX)) and polymer/salt (PEG/Magnesium sulfate) for droplet generation in a flow-focusing geometry. Droplet morphologies and monodispersity in both systems are studied. The PEG/salt system showed an excellent capability of uniform droplet formation with a wide range of sizes (20-60 μm) which makes it a suitable candidate for encapsulation of biological samples. Therefore, we examined the potential application of the PEG/salt system for encapsulating human umbilical vein endothelial cells (HUVECs). A cell viability test was conducted on MgSO4 solutions at various concentrations and our results showed an adequate cell survival. The findings of this research suggest that the polymer/salt ATPS could be a biocompatible all-aqueous platform for cell encapsulation.
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Affiliation(s)
- Mohammad Mastiani
- Center for Biosignatures Discovery Automation, School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287, USA
| | - Negar Firoozi
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA
| | - Nicholas Petrozzi
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA
| | - Seokju Seo
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA
| | - Myeongsub Kim
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA.
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28
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De Lora JA, Fencl FA, Macias Gonzalez AD, Bandegi A, Foudazi R, Lopez GP, Shreve AP, Carroll NJ. Oil-Free Acoustofluidic Droplet Generation for Multicellular Tumor Spheroid Culture. ACS APPLIED BIO MATERIALS 2019; 2:4097-4105. [DOI: 10.1021/acsabm.9b00617] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Jacqueline A. De Lora
- Department of Chemical and Biological Engineering and Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131,United States
| | - Frank A. Fencl
- Department of Chemical and Biological Engineering and Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131,United States
| | - Aidira D.Y. Macias Gonzalez
- Department of Chemical and Biological Engineering and Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131,United States
| | - Alireza Bandegi
- Department of Chemical and Materials Engineering, New Mexico State University, Las Cruces, New Mexico 88003, United States
| | - Reza Foudazi
- Department of Chemical and Materials Engineering, New Mexico State University, Las Cruces, New Mexico 88003, United States
| | - Gabriel P. Lopez
- Department of Chemical and Biological Engineering and Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131,United States
| | - Andrew P. Shreve
- Department of Chemical and Biological Engineering and Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131,United States
| | - Nick J. Carroll
- Department of Chemical and Biological Engineering and Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131,United States
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29
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Choi D, Lee E, Kim SJ, Han M. Passive droplet generation in aqueous two-phase systems with a variable-width microchannel. SOFT MATTER 2019; 15:4647-4655. [PMID: 31073554 DOI: 10.1039/c9sm00469f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Passive droplet generation for an aqueous two-phase system (ATPS) was performed with a fracture-based variable microchannel. A jet of dextran-rich phase (DEX) in a polyethylene-glycol (PEG)-rich phase was created by focused flow. The width of the inlet channel could be varied over the range 1-10 μm via mechanical strain, which extended the range of operational back pressure. This enabled the spontaneous formation of DEX droplets with an ultralow surface tension of 12 μN m-1. The production of DEX droplets were examined with regard to driving pressure, flow rate, DEX/PEG concentration. The droplet properties are analyzed in terms of production rate (2-20 droplets per s), droplet diameter (10-100 μm), and diameter variance (5-20%). Controlling the inlet-channel width with other operating conditions widened the range of droplet properties. This simple and robust method significantly strengthened droplet-generation in microfluidics, especially for ATPS of low solute concentrations relevant to live cells.
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Affiliation(s)
- Daeho Choi
- Mechanical Engineering, Incheon National University, Incheon, 22012, Korea.
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30
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Zou Y, Song J, You X, Yao J, Xie S, Jin M, Wang X, Yan Z, Zhou G, Shui L. Interfacial Complexation Induced Controllable Fabrication of Stable Polyelectrolyte Microcapsules Using All-Aqueous Droplet Microfluidics for Enzyme Release. ACS APPLIED MATERIALS & INTERFACES 2019; 11:21227-21238. [PMID: 31091079 DOI: 10.1021/acsami.9b02788] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Water-in-water (w/w) emulsions are particularly advantageous for biomedical-related applications, such as cell encapsulation, bioreactors, biocompatible storage, and processing of biomacromolecules. However, due to ultralow interfacial tension, generation and stabilization of uniform w/w droplets are challenging. In this work, we report a strategy of creating stable and size-controllable w/w droplets that can quickly form polyelectrolyte microcapsules (PEMCs) in a microfluidic device. A three-phase (inner, middle, outer) aqueous system was applied to create a stream of inner phase, which could be broken into droplets via a mechanical perturbation frequency, with size determined by the stream diameter and vibration frequency. The interfacial complexation is formed via electrostatic interaction of polycations of poly(diallyldimethylammoniumchloride) with polyanions of polystyrene sodium sulfate in the inner and outer phases. With addition of negatively charged silica nanoparticles, the stability, permeability, and mechanical strength of the PEMC shell could be well manipulated. Prepared PEMCs were verified by encapsulating fluorescein isothiocyanate-labeled dextran molecules and stimuli-triggered release by varying the pH value or osmotic pressure. A model enzyme, trypsin, was successfully encapsulated into PEMCs and released without impairing their catalytic activity. These results highlight its potential applications for efficient encapsulation, storage, delivery, and release of chemical, biological, pharmaceutical, and therapeutic agents.
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Affiliation(s)
| | - Jing Song
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research) , 2 Fusionopolis Way, Innovis, #08-03 , 138634 Singapore
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31
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Abbasi N, Navi M, Nunes JK, Tsai SSH. Controlled generation of spiky microparticles by ionic cross-linking within an aqueous two-phase system. SOFT MATTER 2019; 15:3301-3306. [PMID: 30849136 DOI: 10.1039/c8sm02315h] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Microparticles are used in a variety of different fields, such as drug delivery. Recently, non-spherical microparticle generation has become desirable. The high surface-to-volume ratio of non-spherical microparticles allows for enhanced targeting, and attachment to cells and tissue. Current non-spherical microparticle generation techniques require complicated setup, and utilizing natural micrograins, such as pollen grains, as non-spherical delivery vehicles, requires extensive post-processing. Here, we describe a unique and facile chemical synthesis approach, for controlled generation of pollen-like microparticles, based on ionic cross-linking of alginate and calcium chloride (CaCl2), within an all-biocompatible aqueous two-phase system (ATPS) of dextran (DEX) and polyethylene glycol (PEG). Our technique controls the length of spikes that emerge on the surface of these microparticles. We anticipate that these pollen-like spiky microparticles may be used as drug delivery vehicles, and this new chemical synthesis approach may be used for generating other biomaterials.
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Affiliation(s)
- Niki Abbasi
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Canada.
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32
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Aydogan Gokturk P, Ulgut B, Suzer S. AC Electrowetting Modulation of Low-Volatile Liquids Probed by XPS: Dipolar vs Ionic Screening. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:3319-3326. [PMID: 30768276 DOI: 10.1021/acs.langmuir.8b04099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
X-ray photoelectron spectroscopic (XPS) data have been recorded for a low-molecular-weight poly(ethylene glycol) microliter-sized sessile liquid drops sitting on a dielectric covered planar electrode while imposing a ±6 V square-wave actuation with varying frequencies between 10-1 and 105 Hz to tap into the information derivable from (AC) electrowetting. We show that this time-varying XPS spectra reveal two distinct behaviors of the device under investigation, below and above a critical frequency, measured as ∼70 Hz for the liquid poly(ethylene glycol) with a 600 Da molecular weight. Below the critical frequency, the liquid complies faithfully to the applied bias, as determined by the constant shift in the binding energy position of the XPS peaks representative of the liquid throughout its entire surface. The liquid completely screens the applied electrical field and the entire potential drop takes place at the liquid/dielectric interface. However, for frequencies above the critical value, the resistive component of the system dominates, resulting in the formation of equipotential surface contours, which are derived from the differences in the positions of the twinned O 1s peaks under AC application. This critical frequency is independent of the size of the liquid drop, and the amplitude of the excitation, but increases when ionic moieties are introduced. The XP spectra under AC actuation is also faithfully simulated using an equivalent circuit model consisting of only resistors and capacitors and using an electrical circuit simulation software. Moreover, a mimicking device is fabricated and its XP spectra are recorded using the Sn 3d peaks of the solder joints at different points on the circuit to confirm the reliability of the measured and simulated AC behaviors of the liquid. These new findings indicate that in contrast to direct current case, XPS measurements under variable frequency AC actuation reveal (through differences in the frequency response) information related to the chemical makeup of the liquid(s) and brings the laboratory-based XPS as a powerful complimentary arsenal to electrochemical analyses of liquids and their interfaces.
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Affiliation(s)
| | - Burak Ulgut
- Department of Chemistry , Bilkent University , Bilkent , 06800 Ankara , Turkey
| | - Sefik Suzer
- Department of Chemistry , Bilkent University , Bilkent , 06800 Ankara , Turkey
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Liu C, Zheng W, Xie R, Liu Y, Liang Z, Luo G, Ding M, Liang Q. Microfluidic fabrication of water-in-water droplets encapsulated in hydrogel microfibers. CHINESE CHEM LETT 2019. [DOI: 10.1016/j.cclet.2018.09.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Liu M, Zheng Y, Liu Y, Zhang Z, Wang Y, Chen Q, Li J, Li J, Huang Y, Yin Q. Effects of surfactant adsorption on the formation of compound droplets in microfluidic devices. RSC Adv 2019; 9:41943-41954. [PMID: 35541619 PMCID: PMC9076507 DOI: 10.1039/c9ra07141e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 12/02/2019] [Indexed: 11/21/2022] Open
Abstract
Driven by the need to prepare monodisperse compound droplets, the formation mechanism of compound droplets was comprehensively investigated. With increasing poly(vinyl alcohol) (PVA) concentration in the W2 phase, the formation mechanism of inner W1 droplet is not affected while the behavior of the O phase in the W2 phase is different. The W1/O compound droplets can form stably in an inner squeezing – outer dripping regime, but the structure of the W1/O compound droplets are affected by the formation time matching between inner W1 droplet and W1/O compound droplets, which influences the stability of the compound droplets. Moreover, the formation process of the W1/O compound droplet is composed of cone recoiling, neck formation, neck developing, neck thinning and neck pinch-off. The formation time of the W1/O compound droplet is mainly determined the neck formation stage. The higher interfacial tension is unfavorable to the neck formation at the initial stages, but it makes the Laplace pressure difference increasing, which promotes the thinning of the neck in the neck pinch-off stage. The results provide more in-depth insights of the effects of surfactants on the formation of compound droplets, benefiting for preparing monodisperse and stable compound droplets. Profile of neck width versus the relative time during the formation process of W1/O droplets.![]()
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Affiliation(s)
- Meifang Liu
- Research Center of Laser Fusion
- China Academy of Engineering Physics
- Mianyang 621900
- China
| | - Yueqing Zheng
- Institute of Mechanical Manufacturing Technology
- China Academy of Engineering Physics
- Mianyang 621900
- China
| | - Yiyang Liu
- Research Center of Laser Fusion
- China Academy of Engineering Physics
- Mianyang 621900
- China
| | - Zhanwen Zhang
- Research Center of Laser Fusion
- China Academy of Engineering Physics
- Mianyang 621900
- China
| | - Yuguang Wang
- Research Center of Laser Fusion
- China Academy of Engineering Physics
- Mianyang 621900
- China
| | - Qiang Chen
- Research Center of Laser Fusion
- China Academy of Engineering Physics
- Mianyang 621900
- China
| | - Jing Li
- Research Center of Laser Fusion
- China Academy of Engineering Physics
- Mianyang 621900
- China
| | - Jie Li
- Research Center of Laser Fusion
- China Academy of Engineering Physics
- Mianyang 621900
- China
| | - Yawen Huang
- School of Material Science and Engineering
- Southwest University of Science and Technology
- Mianyang
- China
| | - Qiang Yin
- Research Center of Laser Fusion
- China Academy of Engineering Physics
- Mianyang 621900
- China
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Mastiani M, Seo S, Mosavati B, Kim M. High-Throughput Aqueous Two-Phase System Droplet Generation by Oil-Free Passive Microfluidics. ACS OMEGA 2018; 3:9296-9302. [PMID: 31459062 PMCID: PMC6645416 DOI: 10.1021/acsomega.8b01768] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 08/06/2018] [Indexed: 05/29/2023]
Abstract
Aqueous two-phase system (ATPS) droplet generation has significant potential in biological and medical applications because of its excellent biocompatibility. However, the ultralow interfacial tension of ATPS makes droplet generation extremely challenging when compared with the conventional water-in-oil (W/O) system. In this paper, we passively produced ATPS droplets with a wide range of droplet size and high production rate without the involvement of an oil phase and external forces. For the first time, we reported important information of the flow rate and capillary (Ca) number for passive, oil-free ATPS droplet generation. It was found that the range of Ca numbers of the continuous phase under the jetting flow regime is 0.3-1.7, as compared to less than 0.1 in the W/O system, indicating the ultralow interfacial tension in ATPS. In addition, we successfully generated ATPS droplets with a radius as small as 7 μm at the maximum frequency up to 300 Hz, which has not been achieved in previous studies. The size and generation frequency of ATPS droplets can be controlled independently by adjusting the inlet pressures and corresponding flow rates. We found that the droplet size is correlated with the pressure and flow rate ratios with the power-law exponents of 0.8 and 0.2, respectively.
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Chao Y, Mak SY, Ma Q, Wu J, Ding Z, Xu L, Shum HC. Emergence of Droplets at the Nonequilibrium All-Aqueous Interface in a Vertical Hele-Shaw Cell. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:3030-3036. [PMID: 29465242 DOI: 10.1021/acs.langmuir.7b04168] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The interfacial phenomena at liquid-liquid interfaces remain the subject of constant fascination in science and technology. Here, we show that fingers forming at the interface of nonequilibrium all-aqueous systems can spontaneously break into an array of droplets. The dynamic formation of droplets at the water-water (w/w) interface is observed when a less dense aqueous phase, for instance, the dextran solution, is placed on a denser aqueous phase, the polyethylene glycol solution, in a vertical Hele-Shaw cell. Because of the gradual diffusion of water from the upper phase into the lower phase, a dense layer appears at the nonequilibrium w/w interface. As a result, a periodic array of fingers emerge and sink. Remarkably, these fingers break up and an array of droplets are emitted from the interface. We characterize the wavelength of fingering by measuring the average distance between the dominant fingers. By varying the initial concentrations of the two nonequilibrium aqueous phases, we identify experimentally a phase diagram with a wide parameter space in which finger breaking occurs. Finally, plenty of droplets, spontaneously formed when one phase is continuously deposited onto another aqueous phase, further confirm the robustness of our experimental results. Our work suggests a simple yet efficient approach with a potential upscalability to generate all-aqueous droplets.
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Affiliation(s)
- Youchuang Chao
- Department of Mechanical Engineering , The University of Hong Kong , Pokfulam Road , Hong Kong , China
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI) , Shenzhen , Guangdong 518000 , China
| | - Sze Yi Mak
- Department of Mechanical Engineering , The University of Hong Kong , Pokfulam Road , Hong Kong , China
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI) , Shenzhen , Guangdong 518000 , China
| | - Qingming Ma
- Department of Mechanical Engineering , The University of Hong Kong , Pokfulam Road , Hong Kong , China
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI) , Shenzhen , Guangdong 518000 , China
| | - Jing Wu
- Department of Mechanical Engineering , The University of Hong Kong , Pokfulam Road , Hong Kong , China
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI) , Shenzhen , Guangdong 518000 , China
| | - Zijing Ding
- Department of Mechanical Engineering , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Lei Xu
- Department of Physics , The Chinese University of Hong Kong , Hong Kong , China
| | - Ho Cheung Shum
- Department of Mechanical Engineering , The University of Hong Kong , Pokfulam Road , Hong Kong , China
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI) , Shenzhen , Guangdong 518000 , China
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Mak SY, Chao Y, Rahman S, Shum HC. Droplet Formation by Rupture of Vibration-Induced Interfacial Fingers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:926-932. [PMID: 29094601 DOI: 10.1021/acs.langmuir.7b02633] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
By imposing vibration to a core-annular flow of an aqueous two-phase system (ATPS) with ultralow interfacial tension, we observe a liquid finger protruding from the interface of an expanding jet. We find that the protruded finger breaks up only when its length-to-width ratio exceeds a threshold value. The breakup follows a constant wavelength-to-width ratio that is consistent with that of breakup under Rayleigh-Plateau instability. The mechanism is applicable to aqueous two-phase systems with a large range of viscosity ratios. The protruded finger can break up into small droplets that are monodisperse in size, controllable in generation frequency under a wide range of flow rates. This work suggests a way to generate small water-water droplets with high monodispersity and production rate from a single nozzle.
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Affiliation(s)
- Sze Yi Mak
- Department of Mechanical Engineering, The University of Hong Kong , Pok Fu Lam 999077, Hong Kong
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI) , Shenzhen, Guangdong 518000, China
| | - Youchuang Chao
- Department of Mechanical Engineering, The University of Hong Kong , Pok Fu Lam 999077, Hong Kong
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI) , Shenzhen, Guangdong 518000, China
| | - Shakurur Rahman
- Department of Mechanical Engineering, The University of Hong Kong , Pok Fu Lam 999077, Hong Kong
| | - Ho Cheung Shum
- Department of Mechanical Engineering, The University of Hong Kong , Pok Fu Lam 999077, Hong Kong
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI) , Shenzhen, Guangdong 518000, China
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Abbasi N, Navi M, Tsai SSH. Microfluidic Generation of Particle-Stabilized Water-in-Water Emulsions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:213-218. [PMID: 29231744 DOI: 10.1021/acs.langmuir.7b03245] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Herein, we present a microfluidic platform that generates particle-stabilized water-in-water emulsions. The water-in-water system that we use is based on an aqueous two-phase system of polyethylene glycol (PEG) and dextran (DEX). DEX droplets are formed passively, in the continuous phase of PEG and carboxylated particle suspension at a flow-focusing junction inside a microfluidic device. As DEX droplets travel downstream inside the microchannel, carboxylated particles that are in the continuous phase partition to the interface of the DEX droplets due to their affinity to the interface of PEG and DEX. As the DEX droplets become covered with carboxylated particles, they become stabilized against coalescence. We study the coverage and stability of the emulsions, while tuning the concentration and the size of the carboxylated particles, downstream inside the reservoir of the microfluidic device. These particle-stabilized water-in-water emulsions showcase good particle adsorption under shear, while being flowed through narrow microchannels. The intrinsic biocompatibility advantages of particle-stabilized water-in-water emulsions make them a good alternative to traditional particle-stabilized water-in-oil emulsions. To illustrate a biotechnological application of this platform, we show a proof-of-principle of cell encapsulation using this system, which with further development may be used for immunoisolation of cells for transplantation purposes.
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Affiliation(s)
- Niki Abbasi
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto M5B 2K3, Canada
- Institute for Biomedical Engineering, Science and Technology (iBEST)-A Partnership between Ryerson University and St. Michael's Hospital , Toronto M5B 1W8, Canada
| | - Maryam Navi
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto M5B 2K3, Canada
- Institute for Biomedical Engineering, Science and Technology (iBEST)-A Partnership between Ryerson University and St. Michael's Hospital , Toronto M5B 1W8, Canada
| | - Scott S H Tsai
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto M5B 2K3, Canada
- Institute for Biomedical Engineering, Science and Technology (iBEST)-A Partnership between Ryerson University and St. Michael's Hospital , Toronto M5B 1W8, Canada
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Hann SD, Stebe KJ, Lee D. All-Aqueous Assemblies via Interfacial Complexation: Toward Artificial Cell and Microniche Development. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:10107-10117. [PMID: 28882042 DOI: 10.1021/acs.langmuir.7b02237] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In nature, the environment surrounding biomolecules and living cells can dictate their structure, function, and properties. Confinement is a key means to define and regulate such environments. For example, the confinement of appropriate constituents in compartments facilitates the assembly, dynamics, and function of biochemical machineries as well as subcellular organelles. Membraneless organelles, in particular, are thought to form via thermodynamic cues defined within the interior space of cells. On larger length scales, the confinement of living cells dictates cellular function for both mammalian and bacterial cells. One promising class of artificial structures that can recapitulate these multiscale confinement effects is based on aqueous two-phase systems (ATPSs). This feature article highlights recent developments in the production and stabilization of ATPS-droplet-based systems, with a focus on interfacial complexation. These systems enable structure formation, modulation, and triggered (dis)assembly, thereby allowing structures to be tailored to fit the desired function and designed for particular confinement studies. Open issues for both synthetic cells and niche studies are identified.
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Affiliation(s)
- Sarah D Hann
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Kathleen J Stebe
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Daeyeon Lee
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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Zhou C, Zhu P, Tian Y, Tang X, Shi R, Wang L. Microfluidic generation of aqueous two-phase-system (ATPS) droplets by oil-droplet choppers. LAB ON A CHIP 2017; 17:3310-3317. [PMID: 28861566 DOI: 10.1039/c7lc00696a] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Existing approaches for droplet generation with an ultra-low interfacial tension using aqueous two-phase systems, ATPS, are either constricted by a narrow range of flow conditions using passive methods or subjected to complex chip fabrication with the integration of external components using active actuation. To address these issues, we present a simple approach to produce uniform ATPS droplets facilitated by oil-droplet choppers in microfluidics. Our solution counts on the synchronized formation of high-interfacial-tension oil-in-water and low-interfacial-tension water-in-water droplets, where the ATPS interface is distorted by oil droplets and decays into water-in-water droplets. In the synchronization regime, the size and generation frequency of ATPS droplets can be controlled independently by tuning the flow rates of the dispersed aqueous and oil phases, respectively. Our method demonstrates high uniformity of droplets (coefficient of variation between 0.75% and 2.45%), a wide range of available droplet size (droplet radius from 5 μm to 180 μm), and a maximum generation frequency of about 2.1 kHz that is nearly two orders of magnitude faster than that in existing methods. We develop theoretical models to precisely predict the minimum and maximum frequencies of droplet generation and the droplet size. The produced ATPS droplets and oil choppers are separated in the channel using density difference. Our method would boost emulsion-based biological applications such as cell encapsulation, biomolecule delivery, bioreactors, and biomaterials synthesis with ATPS droplets.
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Affiliation(s)
- Chunmei Zhou
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China.
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Abstract
Droplet microfluidics generates and manipulates discrete droplets through immiscible multiphase flows inside microchannels. Due to its remarkable advantages, droplet microfluidics bears significant value in an extremely wide range of area. In this review, we provide a comprehensive and in-depth insight into droplet microfluidics, covering fundamental research from microfluidic chip fabrication and droplet generation to the applications of droplets in bio(chemical) analysis and materials generation. The purpose of this review is to convey the fundamentals of droplet microfluidics, a critical analysis on its current status and challenges, and opinions on its future development. We believe this review will promote communications among biology, chemistry, physics, and materials science.
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Affiliation(s)
- Luoran Shang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, China
| | - Yao Cheng
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, China
| | - Yuanjin Zhao
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, China
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Mak SY, Chao Y, Shum HC. The dripping-to-jetting transition in a co-axial flow of aqueous two-phase systems with low interfacial tension. RSC Adv 2017. [DOI: 10.1039/c6ra26556a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The dripping-to-jetting transition of co-axial flow with high interfacial tension has been extensively studied; however, little is known about this with low interfacial tension.
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Affiliation(s)
- Sze Yi Mak
- Department of Mechanical Engineering
- The University of Hong Kong
- China
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI)
- Shenzhen
| | - Youchuang Chao
- Department of Mechanical Engineering
- The University of Hong Kong
- China
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI)
- Shenzhen
| | - Ho Cheung Shum
- Department of Mechanical Engineering
- The University of Hong Kong
- China
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI)
- Shenzhen
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Mytnyk S, Ziemecka I, Olive AG, van der Meer JWM, Totlani KA, Oldenhof S, Kreutzer MT, van Steijn V, van Esch JH. Microcapsules with a permeable hydrogel shell and an aqueous core continuously produced in a 3D microdevice by all-aqueous microfluidics. RSC Adv 2017. [DOI: 10.1039/c7ra00452d] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We report the continuous production of microcapsules composed of an aqueous core and permeable hydrogel shell, made stable by the controlled photo-cross-linking of the shell of an all-aqueous double emulsion.
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Affiliation(s)
- Serhii Mytnyk
- Advanced Soft Matter Group
- Chemical Engineering Department
- Delft University of Technology
- Delft
- The Netherlands
| | - Iwona Ziemecka
- Advanced Soft Matter Group
- Chemical Engineering Department
- Delft University of Technology
- Delft
- The Netherlands
| | - Alexandre G. L. Olive
- Advanced Soft Matter Group
- Chemical Engineering Department
- Delft University of Technology
- Delft
- The Netherlands
| | - J. Wim M. van der Meer
- Product and Process Engineering Group
- Chemical Engineering Department
- Delft University of Technology
- Delft
- The Netherlands
| | - Kartik A. Totlani
- Product and Process Engineering Group
- Chemical Engineering Department
- Delft University of Technology
- Delft
- The Netherlands
| | - Sander Oldenhof
- Advanced Soft Matter Group
- Chemical Engineering Department
- Delft University of Technology
- Delft
- The Netherlands
| | - Michiel T. Kreutzer
- Product and Process Engineering Group
- Chemical Engineering Department
- Delft University of Technology
- Delft
- The Netherlands
| | - Volkert van Steijn
- Product and Process Engineering Group
- Chemical Engineering Department
- Delft University of Technology
- Delft
- The Netherlands
| | - Jan H. van Esch
- Advanced Soft Matter Group
- Chemical Engineering Department
- Delft University of Technology
- Delft
- The Netherlands
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Vázquez-Villegas P, Ouellet E, González C, Ruiz-Ruiz F, Rito-Palomares M, Haynes CA, Aguilar O. A microdevice assisted approach for the preparation, characterization and selection of continuous aqueous two-phase systems: from micro to bench-scale. LAB ON A CHIP 2016; 16:2662-2672. [PMID: 27302418 DOI: 10.1039/c6lc00333h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Aqueous two-phase systems (ATPS) have emerged as an alternative strategy for the recovery and purification of a wide variety of biological products. Typical process development requires a large screening of experimental conditions towards industrial adoption where continuous processes are preferred. In this work, it was proved that under certain flow conditions, ATPS could be formed continuously inside a microchannel, starting from stocks of phase components. Staggered herringbone chaotic micromixers included within the device sequentially and rapidly prepare two-phase systems across an entire range of useful phase compositions. Two-phase diagrams (binodal curves) were easily plotted using the cloud-point method for systems of different components and compared with previously reported curves for each system, proving that phase formation inside the device correlated with the previously reported diagrams. A proof of concept for sample partitioning in such a microdevice was performed with two different experimental models: BSA and red blood cells. Finally, the microdevice was employed to obtain information about the recovery and partition coefficient of invertase from a real complex mixture of proteins (yeast extract) to design a process for the recovery of the enzyme selecting a suitable system and composition to perform the process at bench-scale.
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Affiliation(s)
- Patricia Vázquez-Villegas
- Escuela de Ingeniería y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, Monterrey, N.L. 64849, Mexico.
| | - Eric Ouellet
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4 Canada
| | - Claudia González
- Escuela de Ingeniería y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, Monterrey, N.L. 64849, Mexico.
| | - Federico Ruiz-Ruiz
- Escuela de Ingeniería y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, Monterrey, N.L. 64849, Mexico.
| | - Marco Rito-Palomares
- Escuela de Ingeniería y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, Monterrey, N.L. 64849, Mexico.
| | - Charles A Haynes
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4 Canada
| | - Oscar Aguilar
- Escuela de Ingeniería y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, Monterrey, N.L. 64849, Mexico.
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Moon BU, Hwang DK, Tsai SSH. Shrinking, growing, and bursting: microfluidic equilibrium control of water-in-water droplets. LAB ON A CHIP 2016; 16:2601-2608. [PMID: 27314278 DOI: 10.1039/c6lc00576d] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We demonstrate the dynamic control of aqueous two phase system (ATPS) droplets in shrinking, growing, and dissolving conditions. The ATPS droplets are formed passively in a flow focusing microfluidic channel, where the dextran-rich (DEX) and polyethylene glycol-rich (PEG) solutions are introduced as disperse and continuous phases, respectively. To vary the ATPS equilibrium condition, we infuse into a secondary inlet the PEG phase from a different polymer concentration ATPS. We find that the resulting alteration of the continuous PEG phase can cause droplets to shrink or grow by approximately 45 and 30%, respectively. This volume change is due to water exchange between the disperse DEX and continuous PEG phases, as the system tends towards new equilibria. We also develop a simple model, based on the ATPS binodal curve and tie lines, that predicts the amount of droplet shrinkage or growth, based on the change in the continuous phase PEG concentration. We observe a good agreement between our experimental results and the model. Additionally, we find that when the continuous phase PEG concentration is reduced such that PEG and DEX phases no longer phase separate, the ATPS droplets are dissolved into the continuous phase. We apply this method to controllably release encapsulated microparticles and cells, and we find that their release occurs within 10 seconds. Our approach uses the dynamic equilibrium of ATPS to control droplet size along the microfluidic channel. By modulating the ATPS equilibrium, we are able to shrink, grow, and dissolve ATPS droplets in situ. We anticipate that this approach may find utility in many biomedical settings, for example, in drug and cell delivery and release applications.
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Affiliation(s)
- Byeong-Ui Moon
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Canada. and Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Canada and Institute for Biomedical Engineering, Science and Technology (iBEST), A partnership between Ryerson University and St. Michael's Hospital, Toronto, Canada
| | - Dae Kun Hwang
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Canada. and Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Canada and Department of Chemical Engineering, Ryerson University, Toronto, Canada
| | - Scott S H Tsai
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Canada. and Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Canada and Institute for Biomedical Engineering, Science and Technology (iBEST), A partnership between Ryerson University and St. Michael's Hospital, Toronto, Canada
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Moon BU, Abbasi N, Jones SG, Hwang DK, Tsai SSH. Water-in-Water Droplets by Passive Microfluidic Flow Focusing. Anal Chem 2016; 88:3982-9. [PMID: 26959358 DOI: 10.1021/acs.analchem.6b00225] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present a simple microfluidic system that generates water-in-water, aqueous two phase system (ATPS) droplets, by passive flow focusing. ATPS droplet formation is achieved by applying weak hydrostatic pressures, with liquid-filled pipette tips as fluid columns at the inlets, to introduce low speed flows to the flow focusing junction. To control the size of the droplets, we systematically vary the interfacial tension and viscosity of the ATPS fluids and adjust the fluid column height at the fluid inlets. The size of the droplets scales with a power law of the ratio of viscous stresses in the two ATPS phases. Overall, we find a drop size coefficient of variation (CV; i.e., polydispersity) of about 10%. We also find that when drops form very close to the flow focusing junction, the drops have a CV of less than 1%. Our droplet generation method is easily scalable: we demonstrate a parallel system that generates droplets simultaneously and improves the droplet production rate by up to one order of magnitude. Finally, we show the potential application of our system for encapsulating cells in water-in-water emulsions by encapsulating microparticles and cells. To the best of our knowledge, our microfluidic technique is the first that forms low interfacial tension ATPS droplets without applying external perturbations. We anticipate that this simple approach will find utility in drug and cell delivery applications because of the all-biocompatible nature of the water-in-water ATPS environment.
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Affiliation(s)
- Byeong-Ui Moon
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto, Canada.,Institute for Biomedical Engineering, Science and Technology (iBEST), a partnership between Ryerson University and St. Michael's Hospital , Toronto, Canada
| | - Niki Abbasi
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto, Canada.,Institute for Biomedical Engineering, Science and Technology (iBEST), a partnership between Ryerson University and St. Michael's Hospital , Toronto, Canada
| | - Steven G Jones
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto, Canada.,Institute for Biomedical Engineering, Science and Technology (iBEST), a partnership between Ryerson University and St. Michael's Hospital , Toronto, Canada
| | - Dae Kun Hwang
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto, Canada.,Institute for Biomedical Engineering, Science and Technology (iBEST), a partnership between Ryerson University and St. Michael's Hospital , Toronto, Canada
| | - Scott S H Tsai
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto, Canada.,Institute for Biomedical Engineering, Science and Technology (iBEST), a partnership between Ryerson University and St. Michael's Hospital , Toronto, Canada
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Breisig H, Wessling M. Droplet formation and shrinking in aqueous two-phase systems using a membrane emulsification method. BIOMICROFLUIDICS 2015; 9:044122. [PMID: 26339321 PMCID: PMC4552692 DOI: 10.1063/1.4929519] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 08/12/2015] [Indexed: 06/05/2023]
Abstract
Using a membrane emulsification method based on porous hollow-fiber membranes in combination with an aqueous two-phase system (ATPS), we are able to produce "water-in-water" droplets with narrow-dispersed size distributions. The equilibrium phases of the aqueous two-phase system polyethylene glycol-dipotassium hydrogen phosphate are used for this purpose. The droplet diameter of a given fluid system is determined by the flow rates of the continuous and disperse phase as well as the hollow fiber dimensions. When diluting the disperse phase and thus moving the ATPS system out of equilibrium, the droplet size can be further reduced in comparison to the equilibrium case. Generally, droplets formed with this method have diameters 20%-60% larger than the inner hollow fiber diameter. The new strategy of diluting the disperse phase allows the production of droplet diameter below the inner diameter of the membrane.
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Song Y, Chan YK, Ma Q, Liu Z, Shum HC. All-Aqueous Electrosprayed Emulsion for Templated Fabrication of Cytocompatible Microcapsules. ACS APPLIED MATERIALS & INTERFACES 2015; 7:13925-33. [PMID: 26053733 DOI: 10.1021/acsami.5b02708] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Encapsulation of biomolecules and cells in hydrogel capsules via emulsion templating frequently induces an irreversible loss of bioactivity, because of the use of nonaqueous solvents. Here, we introduce an all-aqueous electrospray (AAE) approach to generate aqueous two-phase emulsion droplets, and we use them as templates to fabricate microcapsules with preserved cell viability. The approach allows formation of monodisperse microparticles with tunable sizes, variable compositions, and interior architectures in a mild gelation process. This technique potentially benefits a variety of new biomedical applications, such as delivery of bioactive proteins, transplantation of living cells, and assembly of cell-mimicking structures.
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Affiliation(s)
- Yang Song
- ‡HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), Guangdong 518000, China
- †Department of Mechanical Engineering, University of Hong Kong, Hong Kong
| | - Yau Kei Chan
- †Department of Mechanical Engineering, University of Hong Kong, Hong Kong
- §Department of Ophthalmology, University of Hong Kong, Hong Kong
| | - Qingming Ma
- ‡HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), Guangdong 518000, China
- †Department of Mechanical Engineering, University of Hong Kong, Hong Kong
| | - Zhou Liu
- ‡HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), Guangdong 518000, China
- †Department of Mechanical Engineering, University of Hong Kong, Hong Kong
| | - Ho Cheung Shum
- ‡HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), Guangdong 518000, China
- †Department of Mechanical Engineering, University of Hong Kong, Hong Kong
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Moon BU, Jones SG, Hwang DK, Tsai SSH. Microfluidic generation of aqueous two-phase system (ATPS) droplets by controlled pulsating inlet pressures. LAB ON A CHIP 2015; 15:2437-44. [PMID: 25906146 DOI: 10.1039/c5lc00217f] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We present a technique that generates droplets using ultralow interfacial tension aqueous two-phase systems (ATPS). Our method combines a classical microfluidic flow focusing geometry with precisely controlled pulsating inlet pressure, to form monodisperse ATPS droplets. The dextran (DEX) disperse phase enters through the central inlet with variable on-off pressure cycles controlled by a pneumatic solenoid valve. The continuous phase polyethylene glycol (PEG) solution enters the flow focusing junction through the cross channels at a fixed flow rate. The on-off cycles of the applied pressure, combined with the fixed flow rate cross flow, make it possible for the ATPS jet to break up into droplets. We observe different droplet formation regimes with changes in the applied pressure magnitude and timing, and the continuous phase flow rate. We also develop a scaling model to predict the size of the generated droplets, and the experimental results show a good quantitative agreement with our scaling model. Additionally, we demonstrate the potential for scaling-up of the droplet production rate, with a simultaneous two-droplet generating geometry. We anticipate that this simple and precise approach to making ATPS droplets will find utility in biological applications where the all-biocompatibility of ATPS is desirable.
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Affiliation(s)
- Byeong-Ui Moon
- Ryerson University, Mechanical and Industrial Engineering, Toronto, Canada.
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