1
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Nebuloni F, Do QB, Cook PR, Walsh EJ, Wade-Martins R. A fluid-walled microfluidic platform for human neuron microcircuits and directed axotomy. LAB ON A CHIP 2024; 24:3252-3264. [PMID: 38841815 PMCID: PMC11198392 DOI: 10.1039/d4lc00107a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 05/27/2024] [Indexed: 06/07/2024]
Abstract
In our brains, different neurons make appropriate connections; however, there remain few in vitro models of such circuits. We use an open microfluidic approach to build and study neuronal circuits in vitro in ways that fit easily into existing bio-medical workflows. Dumbbell-shaped circuits are built in minutes in standard Petri dishes; the aqueous phase is confined by fluid walls - interfaces between cell-growth medium and an immiscible fluorocarbon, FC40. Conditions are established that ensure post-mitotic neurons derived from human induced pluripotent stem cells (iPSCs) plated in one chamber of a dumbbell remain where deposited. After seeding cortical neurons on one side, axons grow through the connecting conduit to ramify amongst striatal neurons on the other - an arrangement mimicking unidirectional cortico-striatal connectivity. We also develop a moderate-throughput non-contact axotomy assay. Cortical axons in conduits are severed by a media jet; then, brain-derived neurotrophic factor and striatal neurons in distal chambers promote axon regeneration. As additional conduits and chambers are easily added, this opens up the possibility of mimicking complex neuronal networks, and screening drugs for their effects on connectivity.
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Affiliation(s)
- Federico Nebuloni
- Osney Thermofluids Institute, Department of Engineering Science, University of Oxford, Osney Mead, Oxford OX2 0ES, UK.
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Quyen B Do
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford OX1 3QU, UK.
- Kavli Institute for Neuroscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Park Road, Oxford OX1 3QU, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Peter R Cook
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Edmond J Walsh
- Osney Thermofluids Institute, Department of Engineering Science, University of Oxford, Osney Mead, Oxford OX2 0ES, UK.
| | - Richard Wade-Martins
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford OX1 3QU, UK.
- Kavli Institute for Neuroscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Park Road, Oxford OX1 3QU, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
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2
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Nebuloni F, Deroy C, Cook PR, Walsh EJ. Stable diffusion gradients in microfluidic conduits bounded by fluid walls. MICROSYSTEMS & NANOENGINEERING 2024; 10:79. [PMID: 38911344 PMCID: PMC11189932 DOI: 10.1038/s41378-024-00698-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 04/02/2024] [Indexed: 06/25/2024]
Abstract
Assays mimicking in vitro the concentration gradients triggering biological responses like those involved in fighting infections and blood clotting are essential for biomedical research. Microfluidic assays prove especially attractive as they allow precise control of gradient shape allied to a reduction in scale. Conventional microfluidic devices are fabricated using solid plastics that prevent direct access to responding cells. Fluid-walled microfluidics allows the manufacture of circuits on standard Petri dishes in seconds, coupled to simple operating methods; cell-culture medium sitting in a standard dish is confined to circuits by fluid walls made of an immiscible fluorocarbon. We develop and experimentally validate an analytical model of diffusion between two or more aqueous streams flowing at different rates into a fluid-walled conduit with the cross-section of a circular segment. Unlike solid walls, fluid walls morph during flows as pressures fall, with wall shape changing down the conduit. The model is validated experimentally for Fourier numbers < 0.1 using fluorescein diffusing between laminar streams. It enables a priori prediction of concentration gradients throughout a conduit, so allowing rapid circuit design as well as providing bio-scientists with an accurate way of predicting local concentrations of bioactive molecules around responsive and non-responsive cells.
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Affiliation(s)
- Federico Nebuloni
- Department of Engineering Science, Osney Thermo-Fluids Institute, University of Oxford, Oxford, OX2 0ES UK
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE UK
| | - Cyril Deroy
- Department of Engineering Science, Osney Thermo-Fluids Institute, University of Oxford, Oxford, OX2 0ES UK
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE UK
| | - Peter R. Cook
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE UK
| | - Edmond J. Walsh
- Department of Engineering Science, Osney Thermo-Fluids Institute, University of Oxford, Oxford, OX2 0ES UK
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3
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Cheng S, Huang C, Chen W, Zhang P. Directional Superspreading of Water Droplets on Grooved Hydrogel Surfaces for Open Microfluidic Platforms. SMALL METHODS 2024; 8:e2300221. [PMID: 37254259 DOI: 10.1002/smtd.202300221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 05/10/2023] [Indexed: 06/01/2023]
Abstract
Directional liquid spreading has an irreplaceable role in applications such as microfluidic devices, disposable biosensors, and point-of-care diagnostics. However, how to achieve directional, rapid, and complete spreading (i.e., superspreading) of liquids without external energy input is a great challenge. Herein, inspired by the peristome surface of Nepenthes pitcher, the directional superspreading of water droplets on hydrogel surfaces with predesigned microchannels by using the synergistic effect of the liquid-like property of hydrogels and the guidance of anisotropic microstructures is reported. Compared with the smooth ones, hydrogel surfaces with isotropic microstructures can facilitate the superspreading of water droplets, which can be realized within 500 ms in the absence of external forces. Furthermore, directional superspreading and the flow of water droplets are realized under the guidance of anisotropic microgrooves. Such a unique spreading behavior can also be observed on the hydrogel surfaces with various shaped microchannels, such as periodic, bent, shunted, divergent, and confluent morphologies, which have potential for the development of open microfluidic platforms for various healthcare-related applications.
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Affiliation(s)
- Sha Cheng
- Hubei Longzhong Laboratory, Wuhan University of Technology Xiangyang Demonstration Zone, 441000, Xiangyang, China
- Key Laboratory of Advanced Technology for Materials Synthesis and Processing, School of Materials Science and Engineering, Wuhan University of Technology, 430070, Wuhan, China
| | - Cheng Huang
- Hubei Longzhong Laboratory, Wuhan University of Technology Xiangyang Demonstration Zone, 441000, Xiangyang, China
| | - Wen Chen
- Hubei Longzhong Laboratory, Wuhan University of Technology Xiangyang Demonstration Zone, 441000, Xiangyang, China
| | - Pengchao Zhang
- Hubei Longzhong Laboratory, Wuhan University of Technology Xiangyang Demonstration Zone, 441000, Xiangyang, China
- Key Laboratory of Advanced Technology for Materials Synthesis and Processing, School of Materials Science and Engineering, Wuhan University of Technology, 430070, Wuhan, China
- Sanya Science and Education Innovation Park, Wuhan University of Technology, 572024, Sanya, China
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4
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Li C, Hendrikse NW, Mai M, Farooqui MA, Argall-Knapp Z, Kim JS, Wheat EA, Juang T. Microliter whole blood neutrophil assay preserving physiological lifespan and functional heterogeneity. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2023.08.28.23294744. [PMID: 37693613 PMCID: PMC10491351 DOI: 10.1101/2023.08.28.23294744] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
For in vitro neutrophil functional assays, neutrophils are typically isolated from whole blood, having the target cells exposed to an artificial microenvironment with altered kinetics. Isolated neutrophils exhibit limited lifespans of only a few hours ex vivo, significantly shorter than the 3-5 day lifespan of neutrophils in vivo. In addition, due to neutrophil inherently high sensitivity, neutrophils removed from whole blood exhibit stochastic non-specific activation that contributes to assay variability. Here we present a method - named micro-Blood - that enables functional neutrophil assays using a microliter of unprocessed whole blood. micro-Blood allows multiple phenotypic readouts of neutrophil function (including cell/nucleus morphology, motility, recruitment, and pathogen control). In micro-Blood, neutrophils show sustained migration and limited non-specific activation kinetics (<0.1% non-specific activation) over 3-6 days. In contrast, neutrophils isolated using traditional methods show increased and divergent activation kinetics (10-70% non-specific activation) in only 3 h. Finally, micro-Blood allows the capture and quantitative comparison of distinct neutrophil functional heterogeneity between healthy donors and cancer patients in response to microbial stimuli with the preserved physiological lifespan over 6 days.
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5
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Chen Q, Zhai H, Beebe DJ, Li C, Wang B. Visualization-enhanced under-oil open microfluidic system for in situ characterization of multi-phase chemical reactions. Nat Commun 2024; 15:1155. [PMID: 38326343 PMCID: PMC10850056 DOI: 10.1038/s41467-024-45076-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 01/15/2024] [Indexed: 02/09/2024] Open
Abstract
Under-oil open microfluidic system, utilizing liquid-liquid boundaries for confinements, offers inherent advantages including clogging-free flow channels, flexible access to samples, and adjustable gas permeation, making it well-suited for studying multi-phase chemical reactions that are challenging for closed microfluidics. However, reports on the novel system have primarily focused on device fabrication and functionality demonstrations within biology, leaving their application in broader chemical analysis underexplored. Here, we present a visualization-enhanced under-oil open microfluidic system for in situ characterization of multi-phase chemical reactions with Raman spectroscopy. The enhanced system utilizes a semi-transparent silicon (Si) nanolayer over the substrate to enhance visualization in both inverted and upright microscope setups while reducing Raman noise from the substrate. We validated the system's chemical stability and capability to monitor gas evolution and gas-liquid reactions in situ. The enhanced under-oil open microfluidic system, integrating Raman spectroscopy, offers a robust open-microfluidic platform for label-free molecular sensing and real-time chemical/biochemical process monitoring in multi-phase systems.
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Affiliation(s)
- Qiyuan Chen
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Hang Zhai
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - David J Beebe
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
- Department of Pathology and Laboratory Medicine, Madison, WI, 53705, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Chao Li
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI, 53705, USA.
| | - Bu Wang
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA.
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA.
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6
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Zhang Q, Xie T, Yi X, Xing G, Feng S, Chen S, Li Y, Lin JM. Microfluidic Aqueous Two-Phase Focusing of Chemical Species for In Situ Subcellular Stimulation. ACS APPLIED MATERIALS & INTERFACES 2023; 15:45640-45650. [PMID: 37733946 DOI: 10.1021/acsami.3c09665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/23/2023]
Abstract
Confinement of chemical species in a controllable micrometer-level (several to a dozen micrometers) space in an aqueous environment is essential for precisely manipulating chemical events in subcellular regions. However, rapid diffusion and hard-to-control micrometer-level fluids make it a tough challenge. Here, a versatile open microfluidic method based on an aqueous two-phase system (ATPS) is developed to restrict species inside an open space with micron-level width. Unequal standard chemical potentials of the chemical species in two phases and space-time correspondence in the microfluidic system prevent outward diffusion across the phase interface, retaining the target species inside its preferred phase flow and creating a sharp boundary with a dramatic concentration change. Then, the chemical flow (the preferred phase with target chemical species) is precisely manipulated by a microfluidic probe, which can be compressed to a micron-level width and aimed at an arbitrary position of the sample. As a demonstration of the feasibility and versatility of the strategy, chemical flow is successfully applied to subcellular regions of various kinds of living single cells. Subcellular regions are successfully labeled (cytomembrane and mitochondria) and damaged. Healing-regeneration behaviors of living single cells are triggered by subcellular damage and analyzed. The method is relatively general regarding the species of chemicals and biosamples, which could promote deeper cell research.
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Affiliation(s)
- Qiang Zhang
- Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Tianze Xie
- Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Xizhen Yi
- Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Gaowa Xing
- Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Shuo Feng
- Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Shulang Chen
- Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Yuxuan Li
- Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Jin-Ming Lin
- Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
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7
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Li X, Pang X, Jiang H, Duan M, Liu H, Yang Z, Xi Y, Russell TP. Open millifluidics based on powder-encased channels. Proc Natl Acad Sci U S A 2023; 120:e2302907120. [PMID: 37399425 PMCID: PMC10334759 DOI: 10.1073/pnas.2302907120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/31/2023] [Indexed: 07/05/2023] Open
Abstract
Millifluidics, the manipulation of liquid flow in millimeter-sized channels, has been a revolutionary concept in chemical processing and engineering. The solid channels that contain the liquids, though, are not flexible in their design and modification, and prevent contact with the external environment. All-liquid constructs, on the other hand, while flexible and open, are imbedded in a liquid environment. Here, we provide a route to circumvent these limitations by encasing the liquids in a hydrophobic powder in air that jams on the surface, containing and isolating flowing fluids, offering flexibility and adaptability in design, as manifest in the ability to reconfigure, graft, and segment the constructs. Along with the open nature of these powder-contained channels that allow arbitrary connections/disconnections and substance addition/extraction, numerous applications can be opened in the biological, chemical, and material arenas.
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Affiliation(s)
- Xiaoguang Li
- Shaanxi Basic Discipline (Liquid Physics) Research Center, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an, Shaanxi710129, China
| | - Xianglong Pang
- Shaanxi Basic Discipline (Liquid Physics) Research Center, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an, Shaanxi710129, China
| | - Haohao Jiang
- Shaanxi Basic Discipline (Liquid Physics) Research Center, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an, Shaanxi710129, China
| | - Mei Duan
- Shaanxi Basic Discipline (Liquid Physics) Research Center, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an, Shaanxi710129, China
| | - Heng Liu
- Shaanxi Basic Discipline (Liquid Physics) Research Center, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an, Shaanxi710129, China
| | - Zhujun Yang
- Shaanxi Basic Discipline (Liquid Physics) Research Center, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an, Shaanxi710129, China
| | - Yuhang Xi
- Shaanxi Basic Discipline (Liquid Physics) Research Center, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an, Shaanxi710129, China
| | - Thomas P. Russell
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA94720
- Polymer Science and Engineering Department, University of Massachusetts, Conte Center for Polymer Research, Amherst, MA01003
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing100029, China
- Advanced Institute for Materials Research, Tohoku University, Sendai980-8577, Japan
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8
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Niu J, Liu W, Li JX, Pang X, Liu Y, Zhang C, Yue K, Zhou Y, Xu F, Li X, Li F. Machining water through laser cutting of nanoparticle-encased water pancakes. Nat Commun 2023; 14:3853. [PMID: 37386038 DOI: 10.1038/s41467-023-39574-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 06/15/2023] [Indexed: 07/01/2023] Open
Abstract
Due to the inherent disorder and fluidity of water, precise machining of water through laser cutting are challenging. Herein we report a strategy that realizes the laser cutting machining of water through constructing hydrophobic silica nanoparticle-encased water pancakes with sub-millimeter depth. Through theoretical analysis, numerical simulation, and experimental studies, the developed process of nanoparticle-encased water pancake laser cutting and the parameters that affect cutting accuracy are verified and elucidated. We demonstrate that laser-fabricated water patterns can form diverse self-supporting chips (SSCs) with openness, transparency, breathability, liquid morphology, and liquid flow control properties. Applications of laser-fabricated SSCs to various fields, including chemical synthesis, biochemical sensing, liquid metal manipulation, patterned hydrogel synthesis, and drug screening, are also conceptually demonstrated. This work provides a strategy for precisely machining water using laser cutting, addressing existing laser machining challenges and holding significance for widespread fields involving fluid patterning and flow control in biological, chemical, materials and biomedical research.
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Affiliation(s)
- Jicheng Niu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, P.R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an, 710049, P.R. China
| | - Wenjing Liu
- Shaanxi Basic Discipline (Liquid Physics) Research Center, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, China
| | - Jasmine Xinze Li
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an, 710049, P.R. China
| | - Xianglong Pang
- Shaanxi Basic Discipline (Liquid Physics) Research Center, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, China
| | - Yulin Liu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, P.R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an, 710049, P.R. China
| | - Chao Zhang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, P.R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an, 710049, P.R. China
| | - Keyang Yue
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, P.R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an, 710049, P.R. China
| | - Yulin Zhou
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, P.R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an, 710049, P.R. China
| | - Feng Xu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, P.R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an, 710049, P.R. China
| | - Xiaoguang Li
- Shaanxi Basic Discipline (Liquid Physics) Research Center, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, China.
| | - Fei Li
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, P.R. China.
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an, 710049, P.R. China.
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9
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Zeng Y, Khor JW, van Neel TL, Tu WC, Berthier J, Thongpang S, Berthier E, Theberge AB. Miniaturizing chemistry and biology using droplets in open systems. Nat Rev Chem 2023; 7:439-455. [PMID: 37117816 PMCID: PMC10107581 DOI: 10.1038/s41570-023-00483-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2023] [Indexed: 04/30/2023]
Abstract
Open droplet microfluidic systems manipulate droplets on the picolitre-to-microlitre scale in an open environment. They combine the compartmentalization and control offered by traditional droplet-based microfluidics with the accessibility and ease-of-use of open microfluidics, bringing unique advantages to applications such as combinatorial reactions, droplet analysis and cell culture. Open systems provide direct access to droplets and allow on-demand droplet manipulation within the system without needing pumps or tubes, which makes the systems accessible to biologists without sophisticated setups. Furthermore, these systems can be produced with simple manufacturing and assembly steps that allow for manufacturing at scale and the translation of the method into clinical research. This Review introduces the different types of open droplet microfluidic system, presents the physical concepts leveraged by these systems and highlights key applications.
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Affiliation(s)
- Yuting Zeng
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Jian Wei Khor
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Tammi L van Neel
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Wan-Chen Tu
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Jean Berthier
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Sanitta Thongpang
- Department of Chemistry, University of Washington, Seattle, WA, USA
- Department of Biomedical Engineering, Faculty of Engineering, Mahidol University, Nakorn Pathom, Thailand
| | - Erwin Berthier
- Department of Chemistry, University of Washington, Seattle, WA, USA.
| | - Ashleigh B Theberge
- Department of Chemistry, University of Washington, Seattle, WA, USA.
- Department of Urology, School of Medicine, University of Washington, Seattle, WA, USA.
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10
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Li C, McCrone S, Warrick JW, Andes DR, Hite Z, Volk CF, Rose WE, Beebe DJ. Under-oil open microfluidic systems for rapid phenotypic antimicrobial susceptibility testing. LAB ON A CHIP 2023; 23:2005-2015. [PMID: 36883560 PMCID: PMC10581760 DOI: 10.1039/d3lc00066d] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Antimicrobial susceptibility testing (AST) remains the cornerstone of effective antimicrobial selection and optimization in patients. Despite recent advances in rapid pathogen identification and resistance marker detection with molecular diagnostics (e.g., qPCR, MALDI-TOF MS), phenotypic (i.e., microbial culture-based) AST methods - the gold standard in hospitals/clinics - remain relatively unchanged over the last few decades. Microfluidics-based phenotypic AST has been growing fast in recent years, aiming for rapid (i.e., turnaround time <8 h), high-throughput, and automated species identification, resistance detection, and antibiotics screening. In this pilot study, we describe the application of a multi-liquid-phase open microfluidic system, named under-oil open microfluidic systems (UOMS), to achieve a rapid phenotypic AST. UOMS provides an open microfluidics-based solution for rapid phenotypic AST (UOMS-AST) by implementing and recording a pathogen's antimicrobial activity in micro-volume testing units under an oil overlay. UOMS-AST allows free physical access (e.g., by standard pipetting) to the system and label-free, single-cell resolution optical access. UOMS-AST can accurately and rapidly determine antimicrobial activities [including susceptibility/resistance breakpoint and minimum inhibitory concentration (MIC)] from nominal sample/bacterial cells in a system aligned with clinical laboratory standards where open systems and optical microscopy are predominantly adopted. Further, we combine UOMS-AST with a cloud lab data analytic technique for real-time image analysis and report generation to provide a rapid (<4 h) sample-to-report turnaround time, shedding light on its utility as a versatile (e.g., low-resource setting and manual laboratory operation, or high-throughput automated system) phenotypic AST platform for hospital/clinic use.
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Affiliation(s)
- Chao Li
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Sue McCrone
- School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Jay W. Warrick
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - David R. Andes
- Department of Medicine, Division of Infectious Diseases, University of Wisconsin-Madison, Madison, WI 53705, USA
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Zachary Hite
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Cecilia F. Volk
- School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Warren E. Rose
- School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA
- Department of Medicine, Division of Infectious Diseases, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - David J. Beebe
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53705, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA
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11
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Ahmad N. In Vitro and In Vivo Characterization Methods for Evaluation of Modern Wound Dressings. Pharmaceutics 2022; 15:42. [PMID: 36678671 PMCID: PMC9864730 DOI: 10.3390/pharmaceutics15010042] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/10/2022] [Accepted: 12/17/2022] [Indexed: 12/25/2022] Open
Abstract
Chronic wound management represents a major challenge in the healthcare sector owing to its delayed wound-healing process progression and huge financial burden. In this regard, wound dressings provide an appropriate platform for facilitating wound healing for several decades. However, adherent traditional wound dressings do not provide effective wound healing for highly exudating chronic wounds and need the development of newer and innovative wound dressings to facilitate accelerated wound healing. In addition, these dressings need frequent changing, resulting in more pain and discomfort. In order to overcome these issues, a wide range of affordable and innovative modern wound dressings have been developed and explored recently to accelerate and improve the wound healing process. However, a comprehensive understanding of various in vitro and in vivo characterization methods being utilized for the evaluation of different modern wound dressings is lacking. In this context, an overview of modern dressings and their complete in vitro and in vivo characterization methods for wound healing assessment is provided in this review. Herein, various emerging modern wound dressings with advantages and challenges have also been reviewed. Furthermore, different in vitro wound healing assays and in vivo wound models being utilized for the evaluation of wound healing progression and wound healing rate using wound dressings are discussed in detail. Finally, a summary of modern wound dressings with challenges and the future outlook is highlighted.
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Affiliation(s)
- Naveed Ahmad
- Department of Pharmaceutics, College of Pharmacy, Jouf University, Sakaka 72388, Aljouf, Saudi Arabia
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12
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Abstract
Bacteria commonly live in surface-associated communities where steep gradients of antibiotics and other chemical compounds can occur. While many bacterial species move on surfaces, we know surprisingly little about how such antibiotic gradients affect cell motility. Here, we study the behaviour of the opportunistic pathogen Pseudomonas aeruginosa in stable spatial gradients of several antibiotics by tracking thousands of cells in microfluidic devices as they form biofilms. Unexpectedly, these experiments reveal that bacteria use pili-based ('twitching') motility to navigate towards antibiotics. Our analyses suggest that this behaviour is driven by a general response to the effects of antibiotics on cells. Migrating bacteria reach antibiotic concentrations hundreds of times higher than their minimum inhibitory concentration within hours and remain highly motile. However, isolating cells - using fluid-walled microfluidic devices - reveals that these bacteria are terminal and unable to reproduce. Despite moving towards their death, migrating cells are capable of entering a suicidal program to release bacteriocins that kill other bacteria. This behaviour suggests that the cells are responding to antibiotics as if they come from a competing colony growing nearby, inducing them to invade and attack. As a result, clinical antibiotics have the potential to lure bacteria to their death.
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13
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Deroy C, Wheeler JHR, Rumianek AN, Cook PR, Durham WM, Foster KR, Walsh EJ. Reconfigurable Microfluidic Circuits for Isolating and Retrieving Cells of Interest. ACS APPLIED MATERIALS & INTERFACES 2022; 14:25209-25219. [PMID: 35604799 PMCID: PMC9185686 DOI: 10.1021/acsami.2c07177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
Microfluidic devices are widely used in many fields of biology, but a key limitation is that cells are typically surrounded by solid walls, making it hard to access those that exhibit a specific phenotype for further study. Here, we provide a general and flexible solution to this problem that exploits the remarkable properties of microfluidic circuits with fluid walls─transparent interfaces between culture media and an immiscible fluorocarbon that are easily pierced with pipets. We provide two proofs of concept in which specific cell subpopulations are isolated and recovered: (i) murine macrophages chemotaxing toward complement component 5a and (ii) bacteria (Pseudomonas aeruginosa) in developing biofilms that migrate toward antibiotics. We build circuits in minutes on standard Petri dishes, add cells, pump in laminar streams so molecular diffusion creates attractant gradients, acquire time-lapse images, and isolate desired subpopulations in real time by building fluid walls around migrating cells with an accuracy of tens of micrometers using 3D printed adaptors that convert conventional microscopes into wall-building machines. Our method allows live cells of interest to be easily extracted from microfluidic devices for downstream analyses.
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Affiliation(s)
- Cyril Deroy
- Department
of Engineering Science, Osney Thermo-Fluids Laboratory, University of Oxford, Oxford OX2 0ES, U.K.
| | - James H. R. Wheeler
- Department
of Physics and Astronomy, University of
Sheffield, Sheffield S3 7RH, U.K.
- Department
of Zoology, University of Oxford, Oxford OX1 3SZ, U.K.
- Department
of Biochemistry, University of Oxford, Oxford OX1 3QU, U.K.
| | - Agata N. Rumianek
- Sir
William Dunn School of Pathology, University
of Oxford, Oxford OX1 3RE, U.K.
| | - Peter R. Cook
- Sir
William Dunn School of Pathology, University
of Oxford, Oxford OX1 3RE, U.K.
| | - William M. Durham
- Department
of Physics and Astronomy, University of
Sheffield, Sheffield S3 7RH, U.K.
- Department
of Zoology, University of Oxford, Oxford OX1 3SZ, U.K.
| | - Kevin R. Foster
- Department
of Zoology, University of Oxford, Oxford OX1 3SZ, U.K.
- Department
of Biochemistry, University of Oxford, Oxford OX1 3QU, U.K.
| | - Edmond J. Walsh
- Department
of Engineering Science, Osney Thermo-Fluids Laboratory, University of Oxford, Oxford OX2 0ES, U.K.
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14
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Xie T, Zhang Q, Zhang W, Feng S, Lin JM. Inkjet-Patterned Microdroplets as Individual Microenvironments for Adherent Single Cell Culture. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2107992. [PMID: 35362237 DOI: 10.1002/smll.202107992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/26/2022] [Indexed: 06/14/2023]
Abstract
Adhesion of single cells is the foundation of manifold cellular behaviors and life processes. However, investigating the function of a specific cell is still challenging due to deficiency of adhesion or interference from surrounding cells. Herein, an open microfluidic system is reported for culturing adherent single cells, implemented by a micrometer-scale droplet matrix on an inkjet-printed polylysine template. The target cells are isolated from any cell from other droplets, and their adhesion strength is determined to be comparable to conventional petri dishes via an in-situ investigation with a microfluidic extractor. On this proposed platform, isolated single cells are observed to display an entirely distinct spreading behavior featuring total absence of elongation, indicating drastic cell behavior change from their "singleness." This system has high versatility and compatibility for various assaying methods, assuring a promising potential in detailed single cell behavior and cell heterogeneity studies.
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Affiliation(s)
- Tianze Xie
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Tsinghua University, Beijing, 100084, P. R. China
| | - Qiang Zhang
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Tsinghua University, Beijing, 100084, P. R. China
| | - Weifei Zhang
- Division of Chemical Metrology and Analytical Science, National Institute of Metrology, N 3rd Ring Road E 18, Beijing, 100029, P. R. China
| | - Shuo Feng
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Tsinghua University, Beijing, 100084, P. R. China
| | - Jin-Ming Lin
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Tsinghua University, Beijing, 100084, P. R. China
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15
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Li C, Humayun M, Walker GM, Park KY, Connors B, Feng J, Pellitteri Hahn MC, Scarlett CO, Li J, Feng Y, Clark RL, Hefti H, Schrope J, Venturelli OS, Beebe DJ. Under-Oil Autonomously Regulated Oxygen Microenvironments: A Goldilocks Principle-Based Approach for Microscale Cell Culture. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2104510. [PMID: 35118834 PMCID: PMC8981459 DOI: 10.1002/advs.202104510] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/20/2021] [Indexed: 05/14/2023]
Abstract
Oxygen levels in vivo are autonomously regulated by a supply-demand balance, which can be altered in disease states. However, the oxygen levels of in vitro cell culture systems, particularly microscale cell culture, are typically dominated by either supply or demand. Further, the oxygen microenvironment in these systems is rarely monitored or reported. Here, a method to establish and dynamically monitor autonomously regulated oxygen microenvironments (AROM) using an oil overlay in an open microscale cell culture system is presented. Using this method, the oxygen microenvironment is dynamically regulated via the supply-demand balance of the system. Numerical simulation and experimental validation of oxygen transport within multi-liquid-phase, microscale culture systems involving a variety of cell types, including mammalian, fungal, and bacterial cells are presented. Finally, AROM is applied to establish a coculture between cells with disparate oxygen demands-primary intestinal epithelial cells (oxygen consuming) and Bacteroides uniformis (an anaerobic species prevalent in the human gut).
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Affiliation(s)
- Chao Li
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Mouhita Humayun
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Glenn M Walker
- Department of Biomedical Engineering, University of Mississippi University, Madison, MS, 38677, USA
| | - Keon Young Park
- Department of Surgery, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Bryce Connors
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Jun Feng
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Molly C Pellitteri Hahn
- Analytical Instrumentation Center-Mass Spec Facility, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Cameron O Scarlett
- Analytical Instrumentation Center-Mass Spec Facility, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Jiayi Li
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Yanbo Feng
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Ryan L Clark
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Hunter Hefti
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Jonathan Schrope
- School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53726, USA
| | - Ophelia S Venturelli
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - David J Beebe
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53705, USA
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, 53705, USA
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16
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Torabi S, Cai Z, Pham JT, Trinkle CA. Hydrophobic surface patterning with soft, wax-infused micro-stamps. J Colloid Interface Sci 2022; 615:494-500. [PMID: 35150957 DOI: 10.1016/j.jcis.2022.01.118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 11/18/2022]
Abstract
HYPOTHESIS Waxy hydrocarbons diffuse freely in polydimethylsiloxane (PDMS), and this capability can be leveraged to generate inexpensive surface micropatterns that modify adhesion and wetting. EXPERIMENTS Patterns are created by placing a waxy Parafilm sheet on the back of a PDMS stamp containing microscale surface features. When heated, the paraffin liquefies and diffuses through the stamp, creating a thin liquid layer on the micropatterned stamp surface; when placed in contact with a target surface, the layer solidifies and is retained on the target when the stamp is removed. Micropatterns were generated on different materials and surface topographies; pattern geometry was evaluated using optical profilometry and changes in wetting were evaluated using contact angle goniometry. Diffusion of paraffin through PDMS was evaluated using XPS. FINDINGS Wax micropatterns have submicron lateral resolution and thickness ranging from 85 to 380 nm depending on contact time. By using XPS analysis to track paraffin diffusion within the PDMS stamp during this process, we estimate the diffusion coefficient to be 5.3 × 10-7 cm2/s at 65 °C. This means that the paraffin layer at the stamp surface replenishes in less than a second after stamping, so it can be used multiple times without re-inking to deposit complex, multi-layer paraffin patterns.
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Affiliation(s)
- Soroosh Torabi
- Mechanical Engineering, University of Kentucky, Lexington, KY 40506, United States
| | - Zhuoyun Cai
- Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, United States
| | - Jonathan T Pham
- Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, United States
| | - Christine A Trinkle
- Mechanical Engineering, University of Kentucky, Lexington, KY 40506, United States.
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17
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Dev AA, Dunne P, Hermans TM, Doudin B. Fluid Drag Reduction by Magnetic Confinement. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:719-726. [PMID: 34982565 DOI: 10.1021/acs.langmuir.1c02617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The frictional forces of a viscous liquid flow are a major energy loss issue and severely limit microfluidics practical use. Reducing this drag by more than a few tens of percent remain elusive. Here, we show how cylindrical liquid-in-liquid flow leads to drag reduction of 60-99% for sub-mm and mm-sized channels, regardless of whether the viscosity of the transported liquid is larger or smaller than that of the confining one. In contrast to lubrication or sheath flow, we do not require a continuous flow of the confining lubricant, here made of a ferrofluid held in place by magnetic forces. In a laminar flow model with appropriate boundary conditions, we introduce a modified Reynolds number with a scaling that depends on geometrical factors and viscosity ratio of the two liquids. It explains our whole range of data and reveals the key design parameters for optimizing the drag reduction values. Our approach promises a new route for microfluidics designs with pressure gradient reduced by orders of magnitude.
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Affiliation(s)
- Arvind Arun Dev
- Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS, UMR 7504 CNRS-UdS, 67034 Strasbourg, France
- Université de Strasbourg, CNRS, UMR7140, 4 Rue Blaise Pascal, 67081 Strasbourg, France
| | - Peter Dunne
- Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS, UMR 7504 CNRS-UdS, 67034 Strasbourg, France
| | - Thomas M Hermans
- Université de Strasbourg, CNRS, UMR7140, 4 Rue Blaise Pascal, 67081 Strasbourg, France
| | - Bernard Doudin
- Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS, UMR 7504 CNRS-UdS, 67034 Strasbourg, France
- Université de Strasbourg, CNRS, UMR7140, 4 Rue Blaise Pascal, 67081 Strasbourg, France
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18
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Holloway PM. Novel, Emerging Chip Models of the Blood-Brain Barrier and Future Directions. Methods Mol Biol 2022; 2492:193-224. [PMID: 35733046 DOI: 10.1007/978-1-0716-2289-6_11] [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: 06/15/2023]
Abstract
The use of microfluidic chips is now allowing for more advanced modelling of the blood-brain barrier (BBB) in vitro, recapitulating heterotypic interactions, 3D architecture, and physiological flow. This chapter will give an introduction to these new technologies and how they are being applied to model the BBB and neurovascular unit (NVU). A foundational understanding of the fluid dynamics germane to the effective use of these chips will be set and an overview of how physical phenomena at the microscale can be exploited to enable new possibilities to control the cell culture environment. The four main approaches to construct microfluidic blood vessel mimetics will be discussed with examples of how these techniques are being applied to model the BBB and more recently to study specific neurovascular disease processes. Finally, practical guidance will be given for researchers wishing to adopt these new techniques along with a summary of the challenges, limitations faced, and new opportunities opened up by these advanced cell culture systems.
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Affiliation(s)
- Paul M Holloway
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
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19
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Abstract
Lab-on-a-chip devices leverage microfluidic technologies to enable chemical and biological processes at small scales. However, existing microfluidic channel networks are typically designed for the implementation of a single function or a well-defined protocol and do not allow the flexibility and real-time experimental decision-making essential to many scientific applications. In this Perspective, we highlight that reconfigurability and programmability of microfluidic platforms can support new functionalities that are beyond the reach of current lab-on-a-chip systems. We describe the ideal fully reconfigurable microfluidic device that can change its shape and function dynamically, which would allow researchers to tune a microscale experiment with the capacity to make real-time decisions. We review existing technologies that can dynamically control microscale flows, suggest additional physical mechanisms that could be leveraged towards the goal of reconfigurable microfluidics and highlight the importance of these efforts for the broad scientific community.
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20
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Deroy C, Nebuloni F, Cook PR, Walsh EJ. Microfluidics on Standard Petri Dishes for Bioscientists. SMALL METHODS 2021; 5:e2100724. [PMID: 34927960 DOI: 10.1002/smtd.202100724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/17/2021] [Indexed: 06/14/2023]
Abstract
Few microfluidic devices are used in biomedical labs, despite the obvious potential; reasons given include the devices are rarely made with cell-friendly materials, and liquids are inaccessibly buried behind solid confining walls. An open microfluidic approach is reviewed in which aqueous circuits with almost any imaginable 2D shape are fabricated in minutes on standard polystyrene Petri dishes by reshaping two liquids (cell-culture media plus an immiscible and bioinert fluorocarbon, FC40). Then, the aqueous phase becomes confined by fluid FC40 walls firmly pinned to the dish by interfacial forces. Such walls can be pierced at any point with pipets and liquids added or removed through them, while flows can be driven actively using external pumps or passively by exploiting local differences in Laplace pressure. As walls are robust, permeable to O2 plus CO2 , and transparent, cells are grown in incubators and monitored microscopically as usual. It is hoped that this simple, accessible, and affordable fluid-shaping technology provides bioscientists with an easy entrée into microfluidics.
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Affiliation(s)
- Cyril Deroy
- Osney Thermofluids Institute, Department of Engineering Science, University of Oxford, Osney Mead, Oxford, OX2 0ES, UK
| | - Federico Nebuloni
- Osney Thermofluids Institute, Department of Engineering Science, University of Oxford, Osney Mead, Oxford, OX2 0ES, UK
| | - Peter R Cook
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
- iotaSciences Ltd., Begbroke Science Park, Begbroke, Oxford, Oxfordshire, OX5 1PF, UK
| | - Edmond J Walsh
- Osney Thermofluids Institute, Department of Engineering Science, University of Oxford, Osney Mead, Oxford, OX2 0ES, UK
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21
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Zhang P, Shao N, Qin L. Recent Advances in Microfluidic Platforms for Programming Cell-Based Living Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2005944. [PMID: 34270839 DOI: 10.1002/adma.202005944] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/20/2020] [Indexed: 06/13/2023]
Abstract
Cell-based living materials, including single cells, cell-laden fibers, cell sheets, organoids, and organs, have attracted intensive interests owing to their widespread applications in cancer therapy, regenerative medicine, drug development, and so on. Significant progress in materials, microfabrication, and cell biology have promoted the development of numerous promising microfluidic platforms for programming these cell-based living materials with a high-throughput, scalable, and efficient manner. In this review, the recent progress of novel microfluidic platforms for programming cell-based living materials is presented. First, the unique features, categories, and materials and related fabrication methods of microfluidic platforms are briefly introduced. From the viewpoint of the design principles of the microfluidic platforms, the recent significant advances of programming single cells, cell-laden fibers, cell sheets, organoids, and organs in turns are then highlighted. Last, by providing personal perspectives on challenges and future trends, this review aims to motivate researchers from the fields of materials and engineering to work together with biologists and physicians to promote the development of cell-based living materials for human healthcare-related applications.
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Affiliation(s)
- Pengchao Zhang
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX, 77030, USA
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, New York, NY, 10065, USA
| | - Ning Shao
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX, 77030, USA
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, New York, NY, 10065, USA
| | - Lidong Qin
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX, 77030, USA
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, New York, NY, 10065, USA
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22
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Pickering M, Magner M, Keifenheim D, Rhind N. The fission yeast S-phase cyclin Cig2 can drive mitosis. Genetics 2021; 217:1-12. [PMID: 33683349 DOI: 10.1093/genetics/iyaa002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 10/28/2020] [Indexed: 11/14/2022] Open
Abstract
Commitment to mitosis is regulated by cyclin-dependent kinase (CDK) activity. In the fission yeast Schizosaccharomyces pombe, the major B-type cyclin, Cdc13, is necessary and sufficient to drive mitotic entry. Furthermore, Cdc13 is also sufficient to drive S phase, demonstrating that a single cyclin can regulate alternating rounds of replication and mitosis, and providing the foundation of the quantitative model of CDK function. It has been assumed that Cig2, a B-type cyclin expressed only during S phase and incapable of driving mitosis in wild-type cells, was specialized for S-phase regulation. Here, we show that Cig2 is capable of driving mitosis. Cig2/CDK activity drives mitotic catastrophe-lethal mitosis in inviably small cells-in cells that lack CDK inhibition by tyrosine-phosphorylation. Moreover, Cig2/CDK can drive mitosis in the absence of Cdc13/CDK activity and constitutive expression of Cig2 can rescue loss of Cdc13 activity. These results demonstrate that in fission yeast, not only can the presumptive M-phase cyclin drive S phase, but the presumptive S-phase cyclin can drive M phase, further supporting the quantitative model of CDK function. Furthermore, these results provide an explanation, previously proposed on the basis of computational analyses, for the surprising observation that cells expressing a single-chain Cdc13-Cdc2 CDK do not require Y15 phosphorylation for viability. Their viability is due to the fact that in such cells, which lack Cig2/CDK complexes, Cdc13/CDK activity is unable to drive mitotic catastrophe.
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Affiliation(s)
- Mary Pickering
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Mira Magner
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Dan Keifenheim
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Nicholas Rhind
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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23
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Vallone VF, Telugu NS, Fischer I, Miller D, Schommer S, Diecke S, Stachelscheid H. Methods for Automated Single Cell Isolation and Sub-Cloning of Human Pluripotent Stem Cells. ACTA ACUST UNITED AC 2021; 55:e123. [PMID: 32956572 DOI: 10.1002/cpsc.123] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Advances in human pluripotent stem cell (hPSC) techniques have led them to become a widely used and powerful tool for a vast array of applications, including disease modeling, developmental studies, drug discovery and testing, and emerging cell-based therapies. hPSC workflows that require clonal expansion from single cells, such as CRISPR/Cas9-mediated genome editing, face major challenges in terms of efficiency, cost, and precision. Classical sub-cloning approaches depend on limiting dilution and manual colony picking, which are both time-consuming and labor-intensive, and lack a real proof of clonality. Here we describe the application of three different automated cell isolation and dispensing devices that can enhance the single-cell cloning process for hPSCs. In combination with optimized cell culture conditions, these devices offer an attractive alternative compared to manual methods. We explore various aspects of each device system and define protocols for their practical application. Following the workflow described here, single cell-derived hPSC sub-clones from each system maintain pluripotency and genetic stability. Furthermore, the workflows can be applied to uncover karyotypic mosaicism prevalent in bulk hPSC cultures. Our robust automated workflow facilitates high-throughput hPSC clonal selection and expansion, urgently needed in the operational pipelines of hPSC applications. © 2020 The Authors. Basic Protocol: Efficient automated hPSC single cell seeding and clonal expansion using the iotaSciences IsoCell platform Alternate Protocol 1: hPSC single cell seeding and clonal expansion using the Cellenion CellenONE single-cell dispenser Alternate Protocol 2: hPSC single cell seeding and clonal expansion using the Cytena single-cell dispenser Support Protocol 1: Coating cell culture plates with Geltrex Support Protocol 2: hPSC maintenance in defined feeder-free conditions Support Protocol 3: hPSC passaging in clumps Support Protocol 4: Laminin 521 coating of IsoCell plates and 96-well/384-well plates Support Protocol 5: Preparation of medium containing anti-apoptotic small molecules Support Protocol 6: 96- and 384-well target plate preparation prior to single cell seeding Support Protocol 7: Single cell dissociation of hPSCs Support Protocol 8: IsoCell-, CellenONE-, and Cytena-derived hPSC clone subculture and expansion.
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Affiliation(s)
- Valeria Fernandez Vallone
- Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health (BIH), BIH Stem Cell Core Facility, Berlin, Germany
| | - Narasimha Swamy Telugu
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,BIH Stem Cell Core Facility, Berlin Institute of Health (BIH), Berlin, Germany
| | - Iris Fischer
- Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health (BIH), BIH Stem Cell Core Facility, Berlin, Germany
| | - Duncan Miller
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,BIH Stem Cell Core Facility, Berlin Institute of Health (BIH), Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Sandra Schommer
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,BIH Stem Cell Core Facility, Berlin Institute of Health (BIH), Berlin, Germany
| | - Sebastian Diecke
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,BIH Stem Cell Core Facility, Berlin Institute of Health (BIH), Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Harald Stachelscheid
- Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health (BIH), BIH Stem Cell Core Facility, Berlin, Germany
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24
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Sun G, Manning C, Lee GH, Majeed M, Lu H. Microswimmer Combing: Controlling Interfacial Dynamics for Open-Surface Multifunctional Screening of Small Animals. Adv Healthc Mater 2021; 10:e2001887. [PMID: 33890423 DOI: 10.1002/adhm.202001887] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 03/13/2021] [Indexed: 12/31/2022]
Abstract
Image-based screening of multicellular model organisms is critical for both investigating fundamental biology and drug development. Current microfluidic techniques for high-throughput manipulation of small model organisms, although useful, are generally complicated to operate, which impedes their widespread adoption by biology laboratories. To address this challenge, this paper presents an ultrasimple and yet effective approach, "microswimmer combing," to rapidly isolate live small animals on an open-surface array. This approach exploits a dynamic contact line-combing mechanism designed to handle highly active microswimmers. The isolation method is robust, and the device operation is simple for users without a priori experience. The versatile open-surface device enables multiple screening applications, including high-resolution imaging of multicellular organisms, on-demand mutant selection, and multiplexed chemical screening. The simplicity and versatility of this method provide broad access to high-throughput experimentation for biologists and open up new opportunities to study active microswimmers by different scientific communities.
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Affiliation(s)
- Gongchen Sun
- School of Chemical & Biomolecular Engineering Georgia Institute of Technology Atlanta GA 30332 USA
- Petit Institute of Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA 30332 USA
| | - Cassidy‐Arielle Manning
- School of Chemical & Biomolecular Engineering Georgia Institute of Technology Atlanta GA 30332 USA
| | - Ga Hyun Lee
- School of Chemical & Biomolecular Engineering Georgia Institute of Technology Atlanta GA 30332 USA
| | - Maryam Majeed
- Department of Biological Sciences Columbia University New York NY 10027 USA
| | - Hang Lu
- School of Chemical & Biomolecular Engineering Georgia Institute of Technology Atlanta GA 30332 USA
- Petit Institute of Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA 30332 USA
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25
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Zhang Q, Feng S, Lin L, Mao S, Lin JM. Emerging open microfluidics for cell manipulation. Chem Soc Rev 2021; 50:5333-5348. [PMID: 33972984 DOI: 10.1039/d0cs01516d] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cell manipulation is the foundation of biochemical studies, which demands user-friendly, multifunctional and precise tools. Based on flow confinement principles, open microfluidics can control the movement of microscale liquid in open space. Every position of the circuit is accessible to external instruments, making it possible to perform precise treatment and analysis of cells at arbitrary target positions especially at the single-cell/sub-cell level. Benefiting from its unique superiority, various manipulations including patterned cell culture, 3D tissue modelling, localized chemical stimulation, online cellular factor analysis, single cell sampling, partial cell treatment, and subcellular free radical attack can be easily realized. In this tutorial review, we summarize two basic ideas to design open microfluidics: open microfluidic networks and probes. The principles of mainstream open microfluidic methods are explained, and their recent important applications are introduced. Challenges and developing trends of open microfluidics are also discussed.
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Affiliation(s)
- Qiang Zhang
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing, 100084, China.
| | - Shuo Feng
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing, 100084, China.
| | - Ling Lin
- Department of Bioengineering, Beijing Technology and Business University, Beijing 100048, China.
| | - Sifeng Mao
- Department of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Tokyo 192-0397, Japan
| | - Jin-Ming Lin
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing, 100084, China.
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26
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Mandsberg NK, Højgaard J, Joshi SS, Nielsen LH, Boisen A, Hwu ET. Consumer-Grade Inkjet Printer for Versatile and Precise Chemical Deposition. ACS OMEGA 2021; 6:7786-7794. [PMID: 33778290 PMCID: PMC7992151 DOI: 10.1021/acsomega.1c00282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
Two simple, mechanical modifications are introduced to a consumer-grade inkjet printer to greatly increase its applicability. First, roller isolation bars are added to unlock multiple prints on the same substrate without smearing. This enables printing on a diverse set of substrates (rigid, elastic, liquid, granular, and sticky). Second, spring loadings are added to increase the print precision up to 50-fold, which facilitates alignment to a pre-patterned substrate or between successive prints. Utilizing the expanded substrate compatibility and the increased print precision, we explore tunable loading of drug combinations into microdevices. This loading method has promising applications within point-of-care personalized medication. Furthermore, we show how inkjet printers with array-type printheads (in our case, 6 x 90 nozzles) allow for quasi-simultaneous loading of reactants into microfluidic systems. The ability to do a quasi-simultaneous introduction of chemicals may be particularly useful for studies of rapidly reacting systems of three or more reactants, where premature introduction can shift the initial conditions from the intended. We believe that our modifications to an affordable system will inspire researchers to explore the possibilities of inkjet printing even further.
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Affiliation(s)
- Nikolaj Kofoed Mandsberg
- Center for Intelligent Drug
Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN),
Department of Health Technology, Technical
University of Denmark, 2800 Kgs Lyngby, Denmark
| | - Jesper Højgaard
- Center for Intelligent Drug
Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN),
Department of Health Technology, Technical
University of Denmark, 2800 Kgs Lyngby, Denmark
| | - Shreya Suhas Joshi
- Center for Intelligent Drug
Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN),
Department of Health Technology, Technical
University of Denmark, 2800 Kgs Lyngby, Denmark
| | - Line Hagner Nielsen
- Center for Intelligent Drug
Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN),
Department of Health Technology, Technical
University of Denmark, 2800 Kgs Lyngby, Denmark
| | - Anja Boisen
- Center for Intelligent Drug
Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN),
Department of Health Technology, Technical
University of Denmark, 2800 Kgs Lyngby, Denmark
| | - En Te Hwu
- Center for Intelligent Drug
Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN),
Department of Health Technology, Technical
University of Denmark, 2800 Kgs Lyngby, Denmark
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27
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Song SW, Lee S, Choe JK, Kim NH, Kang J, Lee AC, Choi Y, Choi A, Jeong Y, Lee W, Kim JY, Kwon S, Kim J. Direct 2D-to-3D transformation of pen drawings. SCIENCE ADVANCES 2021; 7:7/13/eabf3804. [PMID: 33762344 PMCID: PMC7990349 DOI: 10.1126/sciadv.abf3804] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 02/08/2021] [Indexed: 05/09/2023]
Abstract
Pen drawing is a method that allows simple, inexpensive, and intuitive two-dimensional (2D) fabrication. To integrate such advantages of pen drawing in fabricating 3D objects, we developed a 3D fabrication technology that can directly transform pen-drawn 2D precursors into 3D geometries. 2D-to-3D transformation of pen drawings is facilitated by surface tension-driven capillary peeling and floating of dried ink film when the drawing is dipped into an aqueous monomer solution. Selective control of the floating and anchoring parts of a 2D precursor allowed the 2D drawing to transform into the designed 3D structure. The transformed 3D geometry can then be fixed by structural reinforcement using surface-initiated polymerization. By transforming simple pen-drawn 2D structures into complex 3D structures, our approach enables freestyle rapid prototyping via pen drawing, as well as mass production of 3D objects via roll-to-roll processing.
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Affiliation(s)
- Seo Woo Song
- Bio-MAX Institute, Seoul National University, Seoul 08826, South Korea
| | - Sumin Lee
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, South Korea
| | - Jun Kyu Choe
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea
| | - Na-Hyang Kim
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea
| | - Junwon Kang
- Interdisciplinary Program for Bioengineering, Seoul National University, Seoul 08826, South Korea
| | - Amos Chungwon Lee
- Bio-MAX Institute, Seoul National University, Seoul 08826, South Korea
| | - Yeongjae Choi
- Nano Systems Institute, Seoul National University, Seoul National University, Seoul 08826, South Korea
| | - Ahyoun Choi
- Interdisciplinary Program for Bioengineering, Seoul National University, Seoul 08826, South Korea
| | - Yunjin Jeong
- Bio-MAX Institute, Seoul National University, Seoul 08826, South Korea
| | - Wooseok Lee
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, South Korea
| | - Ju-Young Kim
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea
| | - Sunghoon Kwon
- Bio-MAX Institute, Seoul National University, Seoul 08826, South Korea.
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, South Korea
- Interdisciplinary Program for Bioengineering, Seoul National University, Seoul 08826, South Korea
- Nano Systems Institute, Seoul National University, Seoul National University, Seoul 08826, South Korea
| | - Jiyun Kim
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea.
- Center for Multidimensional Programmable Matter, Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea
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Aroney STN, Poole PS, Sánchez-Cañizares C. Rhizobial Chemotaxis and Motility Systems at Work in the Soil. FRONTIERS IN PLANT SCIENCE 2021; 12:725338. [PMID: 34512702 PMCID: PMC8429497 DOI: 10.3389/fpls.2021.725338] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/06/2021] [Indexed: 05/17/2023]
Abstract
Bacteria navigate their way often as individual cells through their chemical and biological environment in aqueous medium or across solid surfaces. They swim when starved or in response to physical and chemical stimuli. Flagella-driven chemotaxis in bacteria has emerged as a paradigm for both signal transduction and cellular decision-making. By altering motility, bacteria swim toward nutrient-rich environments, movement modulated by their chemotaxis systems with the addition of pili for surface movement. The numbers and types of chemoreceptors reflect the bacterial niche and lifestyle, with those adapted to complex environments having diverse metabolic capabilities, encoding far more chemoreceptors in their genomes. The Alpha-proteobacteria typify the latter case, with soil bacteria such as rhizobia, endosymbionts of legume plants, where motility and chemotaxis are essential for competitive symbiosis initiation, among other processes. This review describes the current knowledge of motility and chemotaxis in six model soil bacteria: Sinorhizobium meliloti, Agrobacterium fabacearum, Rhizobium leguminosarum, Azorhizobium caulinodans, Azospirillum brasilense, and Bradyrhizobium diazoefficiens. Although motility and chemotaxis systems have a conserved core, rhizobia possess several modifications that optimize their movements in soil and root surface environments. The soil provides a unique challenge for microbial mobility, since water pathways through particles are not always continuous, especially in drier conditions. The effectiveness of symbiont inoculants in a field context relies on their mobility and dispersal through the soil, often assisted by water percolation or macroorganism movement or networks. Thus, this review summarizes the factors that make it essential to consider and test rhizobial motility and chemotaxis for any potential inoculant.
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Deroy C, Stovall-Kurtz N, Nebuloni F, Soitu C, Cook PR, Walsh EJ. Predicting flows through microfluidic circuits with fluid walls. MICROSYSTEMS & NANOENGINEERING 2021; 7:93. [PMID: 34804587 PMCID: PMC8599700 DOI: 10.1038/s41378-021-00322-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/03/2021] [Accepted: 10/08/2021] [Indexed: 05/13/2023]
Abstract
The aqueous phase in traditional microfluidics is usually confined by solid walls; flows through such systems are often predicted accurately. As solid walls limit access, open systems are being developed in which the aqueous phase is partly bounded by fluid walls (interfaces with air or immiscible liquids). Such fluid walls morph during flow due to pressure gradients, so predicting flow fields remains challenging. We recently developed a version of open microfluidics suitable for live-cell biology in which the aqueous phase is confined by an interface with an immiscible and bioinert fluorocarbon (FC40). Here, we find that common medium additives (fetal bovine serum, serum replacement) induce elastic no-slip boundaries at this interface and develop a semi-analytical model to predict flow fields. We experimentally validate the model's accuracy for single conduits and fractal vascular trees and demonstrate how flow fields and shear stresses can be controlled to suit individual applications in cell biology.
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Affiliation(s)
- Cyril Deroy
- Department of Engineering Science, Osney Thermo-Fluids Laboratory, University of Oxford, Oxford, OX2 0ES UK
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE UK
| | - Nicholas Stovall-Kurtz
- Department of Engineering Science, Osney Thermo-Fluids Laboratory, University of Oxford, Oxford, OX2 0ES UK
| | - Federico Nebuloni
- Department of Engineering Science, Osney Thermo-Fluids Laboratory, University of Oxford, Oxford, OX2 0ES UK
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE UK
| | - Cristian Soitu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY USA
| | - Peter R. Cook
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE UK
| | - Edmond J. Walsh
- Department of Engineering Science, Osney Thermo-Fluids Laboratory, University of Oxford, Oxford, OX2 0ES UK
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30
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Maximiano EM, Sequinel T, Martins CA, Angnes L, Gonçalves Trindade MA. Newly designed dual-mode electrochemical sensor onto a single polydimethylsiloxane-based chip. Talanta 2021; 221:121611. [DOI: 10.1016/j.talanta.2020.121611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 08/28/2020] [Accepted: 08/29/2020] [Indexed: 01/24/2023]
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31
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Soitu C, Panea M, Castrejón-Pita AA, Cook PR, Walsh EJ. Creating wounds in cell monolayers using micro-jets. BIOMICROFLUIDICS 2021; 15:014108. [PMID: 33598064 PMCID: PMC7872715 DOI: 10.1063/5.0043312] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 01/26/2021] [Indexed: 06/12/2023]
Abstract
Many wound-healing assays are used in cell biology and biomedicine; they are often labor intensive and/or require specialized and costly equipment. We describe a contactless method to create wounds with any imaginable 2D pattern in cell monolayers using the micro-jets of either media or an immiscible and biocompatible fluorocarbon (i.e., FC40). We also combine this with another method that allows automation and multiplexing using standard Petri dishes. A dish is filled with a thin film of media overlaid with FC40, and the two liquids are reshaped into an array of microchambers within minutes. Each chamber in such a grid is isolated from others by the fluid walls of FC40. Cells are now added, allowed to grow into a monolayer, and wounds are created using the microjets; then, healing is monitored by microscopy. As arrays of chambers can be made using media and Petri dishes familiar to biologists, and as dishes fit seamlessly into their incubators, microscopes, and workflows, we anticipate that this assay will find wide application in wound healing.
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Affiliation(s)
- Cristian Soitu
- Osney Thermofluids Institute, Department of Engineering Science, University of Oxford, Osney Mead, Oxford OX2 0ES, United Kingdom
| | - Mirela Panea
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
| | | | - Peter R. Cook
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom
| | - Edmond J. Walsh
- Osney Thermofluids Institute, Department of Engineering Science, University of Oxford, Osney Mead, Oxford OX2 0ES, United Kingdom
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32
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Microfluidic and Microscale Assays to Examine Regenerative Strategies in the Neuro Retina. MICROMACHINES 2020; 11:mi11121089. [PMID: 33316971 PMCID: PMC7763644 DOI: 10.3390/mi11121089] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/03/2020] [Accepted: 12/05/2020] [Indexed: 12/15/2022]
Abstract
Bioengineering systems have transformed scientific knowledge of cellular behaviors in the nervous system (NS) and pioneered innovative, regenerative therapies to treat adult neural disorders. Microscale systems with characteristic lengths of single to hundreds of microns have examined the development and specialized behaviors of numerous neuromuscular and neurosensory components of the NS. The visual system is comprised of the eye sensory organ and its connecting pathways to the visual cortex. Significant vision loss arises from dysfunction in the retina, the photosensitive tissue at the eye posterior that achieves phototransduction of light to form images in the brain. Retinal regenerative medicine has embraced microfluidic technologies to manipulate stem-like cells for transplantation therapies, where de/differentiated cells are introduced within adult tissue to replace dysfunctional or damaged neurons. Microfluidic systems coupled with stem cell biology and biomaterials have produced exciting advances to restore vision. The current article reviews contemporary microfluidic technologies and microfluidics-enhanced bioassays, developed to interrogate cellular responses to adult retinal cues. The focus is on applications of microfluidics and microscale assays within mammalian sensory retina, or neuro retina, comprised of five types of retinal neurons (photoreceptors, horizontal, bipolar, amacrine, retinal ganglion) and one neuroglia (Müller), but excludes the non-sensory, retinal pigmented epithelium.
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Soitu C, Stovall‐Kurtz N, Deroy C, Castrejón‐Pita AA, Cook PR, Walsh EJ. Jet-Printing Microfluidic Devices on Demand. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2001854. [PMID: 33304750 PMCID: PMC7709972 DOI: 10.1002/advs.202001854] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/22/2020] [Indexed: 05/14/2023]
Abstract
There is an unmet demand for microfluidics in biomedicine. This paper describes contactless fabrication of microfluidic circuits on standard Petri dishes using just a dispensing needle, syringe pump, three-way traverse, cell-culture media, and an immiscible fluorocarbon (FC40). A submerged microjet of FC40 is projected through FC40 and media onto the bottom of a dish, where it washes media away to leave liquid fluorocarbon walls pinned to the substrate by interfacial forces. Such fluid walls can be built into almost any imaginable 2D circuit in minutes, which is exploited to clone cells in a way that beats the Poisson limit, subculture adherent cells, and feed arrays of cells continuously for a week. This general method should have wide application in biomedicine.
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Affiliation(s)
- Cristian Soitu
- Osney Thermofluids InstituteDepartment of Engineering ScienceUniversity of OxfordOsney MeadOxfordOX2 0ESUK
| | - Nicholas Stovall‐Kurtz
- Osney Thermofluids InstituteDepartment of Engineering ScienceUniversity of OxfordOsney MeadOxfordOX2 0ESUK
| | - Cyril Deroy
- Osney Thermofluids InstituteDepartment of Engineering ScienceUniversity of OxfordOsney MeadOxfordOX2 0ESUK
| | | | - Peter R. Cook
- The Sir William Dunn School of PathologyUniversity of OxfordSouth Parks RoadOxfordOX1 3REUK
- Iota Sciences Ltd.Begbroke Science Park, BegbrokeOxfordshireOX5 1PFUK
| | - Edmond J. Walsh
- Osney Thermofluids InstituteDepartment of Engineering ScienceUniversity of OxfordOsney MeadOxfordOX2 0ESUK
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Li H, Shen R, Dong C, Chen T, Jia Y, Mak PI, Martins RP. Turning on/off satellite droplet ejection for flexible sample delivery on digital microfluidics. LAB ON A CHIP 2020; 20:3709-3719. [PMID: 32974634 DOI: 10.1039/d0lc00701c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Digital microfluidics has the potential to minimize and automate reactions in biochemical labs. However, the complexity of drop manipulation and sample preparation on-chip has limited its incorporation into daily workflow. In this paper, we report a novel method for flexible sample delivery on digital microfluidics in a wide volume range spanning four orders of magnitude from picoliters to nanoliters. The method is based on the phenomenon of satellite droplet ejection, triggered by a sudden change in the strength of the electric field across a drop on a hydrophobic dielectric surface. By precisely modulating the actuation signal with convenient external electric controls, satellite droplet ejection can be turned on to dispense samples or turned off to transport picking-up drops. A pico-dosing design is presented and validated in this work to demonstrate the direct and flexible on-chip sample delivery. This approach could pave the way for the acceptance of microfluidics as a common platform for daily reactions to realize lab-on-a-chip.
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Affiliation(s)
- Haoran Li
- The State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau SAR, China.
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35
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Hermann M, Bachus K, Gibson GTT, Oleschuk RD. Open sessile droplet viscometer with low sample consumption. LAB ON A CHIP 2020; 20:1869-1876. [PMID: 32347278 DOI: 10.1039/d0lc00248h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This paper reports a portable viscometer that requires less than 10 μL of sample for a measurement. Using a two-droplet Laplace-induced pumping system on an open microfluidic substrate, the device measures the viscosity of a liquid by determining the time required for one droplet to completely pump into a second droplet. The pumping behaviour follows the Hagen-Poiseuille and Laplace relations where the flow rate, Q, is proportional to the liquid's kinematic viscosity, μ. The progress of pumping is measured by tracking the change in curvature of one of the droplets using a laser that is positioned perpendicular to the microfluidic chip and directed at the "tail" of the shrinking droplet. The angle of incidence and degree of refraction changes depending on the size of the droplet, which is tracked by a linear diode array placed beneath the microfluidic chip. Droplet reservoirs and connecting channels were defined by precise patterning of a glass substrate coated with a commercially available omniphobic coating (Ultra Ever Dry®) using laser micromachining. A 500 μm wide and 20 mm long channel with circular reservoirs (d = 1.5 mm) enabled the measurement of dynamic viscosities in the range of η = 1.0-2.87 mPa s. The materials cost for the entire viscometer (fluidics and electronics, etc.) is <15 USD.
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Affiliation(s)
- Matthias Hermann
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada.
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36
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Zhang T, Lih D, Nagao RJ, Xue J, Berthier E, Himmelfarb J, Zheng Y, Theberge AB. Open microfluidic coculture reveals paracrine signaling from human kidney epithelial cells promotes kidney specificity of endothelial cells. Am J Physiol Renal Physiol 2020; 319:F41-F51. [PMID: 32390509 DOI: 10.1152/ajprenal.00069.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Endothelial cells (ECs) from different human organs possess organ-specific characteristics that support specific tissue regeneration and organ development. EC specificity is identified by both intrinsic and extrinsic cues, among which the parenchyma and organ-specific microenvironment are critical contributors. These extrinsic cues are, however, largely lost during ex vivo cultures. Outstanding challenges remain to understand and reestablish EC organ specificity for in vitro studies to recapitulate human organ-specific physiology. Here, we designed an open microfluidic platform to study the role of human kidney tubular epithelial cells in supporting EC specificity. The platform consists of two independent cell culture regions segregated with a half wall; culture media are added to connect the two culture regions at a desired time point, and signaling molecules can travel across the half wall (paracrine signaling). Specifically, we report that in the microscale coculture device, primary human kidney proximal tubule epithelial cells (HPTECs) rescued primary human kidney peritubular microvascular EC (HKMEC) monolayer integrity and fenestra formation and that HPTECs upregulated key HKMEC kidney-specific genes (hepatocyte nuclear factor 1 homeobox B, adherens junctions-associated protein 1, and potassium voltage-gated channel subfamily J member 16) and endothelial activation genes (vascular cell adhesion molecule-1, matrix metalloproteinase-7, and matrix metalloproteinase-10) in coculture. Coculturing with HPTECs also promoted kidney-specific genotype expression in human umbilical vein ECs and human pluripotent stem cell-derived ECs. Compared with culture in HPTEC conditioned media, coculture of ECs with HPTECs showed increased upregulation of kidney-specific genes, suggesting potential bidirectional paracrine signaling. Importantly, our device is compatible with standard pipettes, incubators, and imaging readouts and could also be easily adapted to study cell signaling between other rare or sensitive cells.
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Affiliation(s)
- Tianzi Zhang
- Department of Chemistry, University of Washington, Seattle, Washington
| | - Daniel Lih
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Ryan J Nagao
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Jun Xue
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Erwin Berthier
- Department of Chemistry, University of Washington, Seattle, Washington
| | - Jonathan Himmelfarb
- Division of Nephrology, Department of Medicine, University of Washington, Seattle, Washington.,Kidney Research Institute, University of Washington, Seattle, Washington
| | - Ying Zheng
- Department of Bioengineering, University of Washington, Seattle, Washington.,Kidney Research Institute, University of Washington, Seattle, Washington.,Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington
| | - Ashleigh B Theberge
- Department of Chemistry, University of Washington, Seattle, Washington.,Kidney Research Institute, University of Washington, Seattle, Washington.,Department of Urology, University of Washington, Seattle, Washington
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37
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Dunne P, Adachi T, Dev AA, Sorrenti A, Giacchetti L, Bonnin A, Bourdon C, Mangin PH, Coey J, Doudin B, Hermans TM. Liquid flow and control without solid walls. Nature 2020; 581:58-62. [DOI: 10.1038/s41586-020-2254-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 02/26/2020] [Indexed: 11/09/2022]
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38
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Li C, Hite Z, Warrick JW, Li J, Geller SH, Trantow VG, McClean MN, Beebe DJ. Under oil open-channel microfluidics empowered by exclusive liquid repellency. SCIENCE ADVANCES 2020; 6:eaay9919. [PMID: 32494607 PMCID: PMC7164933 DOI: 10.1126/sciadv.aay9919] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 12/30/2019] [Indexed: 05/04/2023]
Abstract
Recently, the functionality of under oil open microfluidics was expanded from droplet-based operations to include lateral flow in under oil aqueous channels. However, the resolution of the under oil fluidic channels reported so far is still far from comparable with that of closed-channel microfluidics (millimeters versus micrometers). Here, enabled by exclusive liquid repellency and an under oil sweep technique, open microchannels can now be prepared under oil (rather than in air), which shrinks the channel dimensions up to three orders of magnitude compared to previously reported techniques. Spatial trapping of different cellular samples and advanced control of mass transport (i.e., enhanced upper limit of flow rate, steady flow with passive pumping, and reversible fluidic valves) were achieved with open-channel designs. We apply these functional advances to enable dynamic measurements of dispersion from a pathogenic fungal biofilm. The ensemble of added capabilities reshapes the potential application space for open microfluidics.
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Affiliation(s)
- Chao Li
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Zachary Hite
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Jay W. Warrick
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Jiayi Li
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Stephanie H. Geller
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Victoria G. Trantow
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Megan N. McClean
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53705, USA
- Corresponding author. (D.J.B.); (M.N.M.)
| | - David J. Beebe
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53705, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53705, USA
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA
- Corresponding author. (D.J.B.); (M.N.M.)
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Nelson AZ, Kundukad B, Wong WK, Khan SA, Doyle PS. Embedded droplet printing in yield-stress fluids. Proc Natl Acad Sci U S A 2020; 117:5671-5679. [PMID: 32127482 PMCID: PMC7084155 DOI: 10.1073/pnas.1919363117] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Microfluidic tools and techniques for manipulating fluid droplets have become core to many scientific and technological fields. Despite the plethora of existing approaches to fluidic manipulation, non-Newtonian fluid phenomena are rarely taken advantage of. Here we introduce embedded droplet printing-a system and methods for the generation, trapping, and processing of fluid droplets within yield-stress fluids, materials that exhibit extreme shear thinning. This technique allows for the manipulation of droplets under conditions that are simply unattainable with conventional microfluidic methods, namely the elimination of exterior influences including convection and solid boundaries. Because of this, we believe embedded droplet printing approaches an ideal for the experimentation, processing, or observation of many samples in an "absolutely quiescent" state, while also removing some troublesome aspects of microfluidics including the use of surfactants and the complexity of device manufacturing. We characterize a model material system to understand the process of droplet generation inside yield-stress fluids and develop a nascent set of archetypal operations that can be performed with embedded droplet printing. With these principles and tools, we demonstrate the benefits and versatility of our method, applying it toward the diverse applications of pharmaceutical crystallization, microbatch chemical reactions, and biological assays.
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Affiliation(s)
- Arif Z Nelson
- Biological Systems and Micromechanics, Singapore-MIT Alliance for Research and Technology, 138602 Singapore, Singapore
- Campus for Research Excellence and Technological Enterprise, 138602 Singapore, Singapore
| | - Binu Kundukad
- Biological Systems and Micromechanics, Singapore-MIT Alliance for Research and Technology, 138602 Singapore, Singapore
- Campus for Research Excellence and Technological Enterprise, 138602 Singapore, Singapore
| | - Wai Kuan Wong
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 117585 Singapore, Singapore
| | - Saif A Khan
- Campus for Research Excellence and Technological Enterprise, 138602 Singapore, Singapore;
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 117585 Singapore, Singapore
| | - Patrick S Doyle
- Biological Systems and Micromechanics, Singapore-MIT Alliance for Research and Technology, 138602 Singapore, Singapore;
- Campus for Research Excellence and Technological Enterprise, 138602 Singapore, Singapore
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
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40
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Wang S, Yang X, Wu F, Min L, Chen X, Hou X. Inner Surface Design of Functional Microchannels for Microscale Flow Control. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1905318. [PMID: 31793747 DOI: 10.1002/smll.201905318] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 11/03/2019] [Indexed: 05/05/2023]
Abstract
Fluidic flow behaviors in microfluidics are dominated by the interfaces created between the fluids and the inner surface walls of microchannels. Microchannel inner surface designs, including the surface chemical modification, and the construction of micro-/nanostructures, are good examples of manipulating those interfaces between liquids and surfaces through tuning the chemical and physical properties of the inner walls of the microchannel. Therefore, the microchannel inner surface design plays critical roles in regulating microflows to enhance the capabilities of microfluidic systems for various applications. Most recently, the rapid progresses in micro-/nanofabrication technologies and fundamental materials have also made it possible to integrate increasingly complex chemical and physical surface modification strategies with the preparation of microchannels in microfluidics. Besides, a wave of researches focusing on the ideas of using liquids as dynamic surface materials is identified, and the unique characteristics endowed with liquid-liquid interfaces have revealed that the interesting phenomena can extend the scope of interfacial interactions determining microflow behaviors. This review extensively discusses the microchannel inner surface designs for microflow control, especially evaluates them from the perspectives of the interfaces resulting from the inner surface designs. In addition, prospective opportunities for the development of surface designs of microchannels, and their applications are provided with the potential to attract scientific interest in areas related to the rapid development and applications of various microchannel systems.
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Affiliation(s)
- Shuli Wang
- College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China
- Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen, 361005, China
| | - Xian Yang
- College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China
| | - Feng Wu
- Bionic and Soft Matter Research Institute, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China
- Fujian Provincial Key Laboratory for Soft Functional Materials Research, Xiamen University, Xiamen, 361005, China
| | - Lingli Min
- College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China
| | - Xinyu Chen
- College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China
| | - Xu Hou
- College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China
- Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen, 361005, China
- Bionic and Soft Matter Research Institute, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China
- Fujian Provincial Key Laboratory for Soft Functional Materials Research, Xiamen University, Xiamen, 361005, China
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Day JH, Nicholson TM, Su X, van Neel TL, Clinton I, Kothandapani A, Lee J, Greenberg MH, Amory JK, Walsh TJ, Muller CH, Franco OE, Jefcoate CR, Crawford SE, Jorgensen JS, Theberge AB. Injection molded open microfluidic well plate inserts for user-friendly coculture and microscopy. LAB ON A CHIP 2020; 20:107-119. [PMID: 31712791 PMCID: PMC6917835 DOI: 10.1039/c9lc00706g] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Open microfluidic cell culture systems are powerful tools for interrogating biological mechanisms. We have previously presented a microscale cell culture system, based on spontaneous capillary flow of biocompatible hydrogels, that is integrated into a standard cell culture well plate, with flexible cell compartment geometries and easy pipet access. Here, we present two new injection molded open microfluidic devices that also easily insert into standard cell culture well plates and standard culture workflows, allowing seamless adoption by biomedical researchers. These platforms allow culture and study of soluble factor communication among multiple cell types, and the microscale dimensions are well-suited for rare primary cells. Unique advances include optimized evaporation control within the well, manufacture with reproducible and cost-effective rapid injection molding, and compatibility with sample preparation workflows for high resolution microscopy (following well-established coverslip mounting procedures). In this work, we present several use cases that highlight the usability and widespread utility of our platform including culture of limited primary testis cells from surgical patients, microscopy readouts including immunocytochemistry and single molecule fluorescence in situ hybridization (smFISH), and coculture to study interactions between adipocytes and prostate cancer cells.
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Affiliation(s)
- John H Day
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195, USA.
| | - Tristan M Nicholson
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195, USA. and Department of Urology, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Xiaojing Su
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195, USA.
| | - Tammi L van Neel
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195, USA.
| | - Ivor Clinton
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195, USA.
| | - Anbarasi Kothandapani
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jinwoo Lee
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA and Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Max H Greenberg
- Department of Surgery, NorthShore University Research Institute, Affiliate of University of Chicago Pritzker School of Medicine, Evanston, IL 60201, USA
| | - John K Amory
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Thomas J Walsh
- Department of Urology, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Charles H Muller
- Department of Urology, University of Washington School of Medicine, Seattle, WA 98195, USA and Male Fertility Laboratory, Department of Urology, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Omar E Franco
- Department of Surgery, NorthShore University Research Institute, Affiliate of University of Chicago Pritzker School of Medicine, Evanston, IL 60201, USA
| | - Colin R Jefcoate
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Susan E Crawford
- Department of Surgery, NorthShore University Research Institute, Affiliate of University of Chicago Pritzker School of Medicine, Evanston, IL 60201, USA
| | - Joan S Jorgensen
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Ashleigh B Theberge
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195, USA. and Department of Urology, University of Washington School of Medicine, Seattle, WA 98195, USA
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Soitu C, Deroy C, Castrejón-Pita AA, Cook PR, Walsh EJ. Using Fluid Walls for Single-Cell Cloning Provides Assurance in Monoclonality. SLAS Technol 2019; 25:267-275. [PMID: 31815577 DOI: 10.1177/2472630319891135] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Single-cell isolation and cloning are essential steps in many applications, ranging from the production of biotherapeutics to stem cell therapy. Having confidence in monoclonality in such applications is essential from both research and commercial perspectives, for example, to ensure that data are of high quality and regulatory requirements are met. Consequently, several approaches have been developed to improve confidence in monoclonality. However, ensuring monoclonality using standard well plate formats remains challenging, primarily due to edge effects; the solid wall around a well can prevent a clear view of how many cells might be in a well. We describe a method that eliminates such edge effects: solid confining walls are replaced by transparent fluid ones, and standard low-cost optics can confirm monoclonality.
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Affiliation(s)
- Cristian Soitu
- Department of Engineering Science, University of Oxford, Oxford, UK
| | - Cyril Deroy
- Department of Engineering Science, University of Oxford, Oxford, UK
| | | | - Peter R Cook
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Edmond J Walsh
- Department of Engineering Science, University of Oxford, Oxford, UK
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43
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Feng S, Mao S, Dou J, Li W, Li H, Lin JM. An open-space microfluidic chip with fluid walls for online detection of VEGF via rolling circle amplification. Chem Sci 2019; 10:8571-8576. [PMID: 31803431 PMCID: PMC6839512 DOI: 10.1039/c9sc02974e] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 07/24/2019] [Indexed: 12/17/2022] Open
Abstract
We report an open-space microfluidic chip with fluid walls, integrating functions of cell culture and online detection of secreted proteins controlled by the interfacial tension value.
Despite traditional poly-dimethyl siloxane (PDMS) microfluidic devices having great potential in various biological studies, they are limited by sophisticated fabrication processes and low utilization. An easily controlled microfluidic platform with high efficiency and low cost is desperately required. In this work, we present an open-space microfluidic chip with fluid walls, integrating cell culture and online semi-quantitative detection of vascular endothelial growth factor (VEGF) via rolling circle amplification (RCA) reaction. In comparison with conventional co-culture detecting platforms, this method features the prominent advantages of saving reagents and time, a simplified chip fabrication process, and avoiding additional assistance for online detection with the help of an interfacial tension valve. On such a multi-functional microfluidic chip, cells (human umbilical vein endothelial cells and malignant glioma cells) could maintain regular growth and cell viability. VEGF could be detected with excellent specificity and good linearity in the range of 10–250 pg mL–1. Meanwhile, VEGF secreted by malignant glioma cells was also detected online and obviously increased when cells were stimulated by deferoxamine (DFO) to mimic a hypoxic microenvironment. The designed biochip with fluid walls provides a new perspective for micro-total analysis and could be promisingly applied in future clinical diagnosis and drug analysis.
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Affiliation(s)
- Shuo Feng
- Department of Chemistry , Beijing Key Laboratory of Microanalytical Methods and Instrumentation , MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology , Tsinghua University , Beijing 100084 , China .
| | - Sifeng Mao
- Department of Chemistry , Beijing Key Laboratory of Microanalytical Methods and Instrumentation , MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology , Tsinghua University , Beijing 100084 , China .
| | - Jinxin Dou
- Department of Chemistry , Beijing Key Laboratory of Microanalytical Methods and Instrumentation , MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology , Tsinghua University , Beijing 100084 , China .
| | - Weiwei Li
- Department of Chemistry , Beijing Key Laboratory of Microanalytical Methods and Instrumentation , MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology , Tsinghua University , Beijing 100084 , China .
| | - Haifang Li
- Department of Chemistry , Beijing Key Laboratory of Microanalytical Methods and Instrumentation , MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology , Tsinghua University , Beijing 100084 , China .
| | - Jin-Ming Lin
- Department of Chemistry , Beijing Key Laboratory of Microanalytical Methods and Instrumentation , MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology , Tsinghua University , Beijing 100084 , China .
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44
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Abstract
Open microfluidic capillary systems are a rapidly evolving branch of microfluidics where fluids are manipulated by capillary forces in channels lacking physical walls on all sides. Typical channel geometries include grooves, rails, or beams and complex systems with multiple air-liquid interfaces. Removing channel walls allows access for retrieval (fluid sampling) and addition (pipetting reagents or adding objects like tissue scaffolds) at any point in the channel; the entire channel becomes a "device-to-world" interface, whereas such interfaces are limited to device inlets and outlets in traditional closed-channel microfluidics. Open microfluidic capillary systems are simple to fabricate and reliable to operate. Prototyping methods (e.g., 3D printing) and manufacturing methods (e.g., injection molding) can be used seamlessly, accelerating development. This Perspective highlights fundamentals of open microfluidic capillary systems including unique advantages, design considerations, fabrication methods, and analytical considerations for flow; device features that can be combined to create a "toolbox" for fluid manipulation; and applications in biology, diagnostics, chemistry, sensing, and biphasic applications.
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Affiliation(s)
- Erwin Berthier
- University of Washington, Department of Chemistry, Seattle, Washington 98195, USA
| | - Ashley M. Dostie
- University of Washington, Department of Chemistry, Seattle, Washington 98195, USA
| | - Ulri N. Lee
- University of Washington, Department of Chemistry, Seattle, Washington 98195, USA
| | - Jean Berthier
- University of Washington, Department of Chemistry, Seattle, Washington 98195, USA
| | - Ashleigh B. Theberge
- University of Washington, Department of Chemistry, Seattle, Washington 98195, USA
- University of Washington School of Medicine, Department of Urology, Seattle, Washington 98105, USA
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45
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Friese A, Ursu A, Hochheimer A, Schöler HR, Waldmann H, Bruder JM. The Convergence of Stem Cell Technologies and Phenotypic Drug Discovery. Cell Chem Biol 2019; 26:1050-1066. [PMID: 31231030 DOI: 10.1016/j.chembiol.2019.05.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 04/04/2019] [Accepted: 05/20/2019] [Indexed: 02/06/2023]
Abstract
Recent advances in induced pluripotent stem cell technologies and phenotypic screening shape the future of bioactive small-molecule discovery. In this review we analyze the impact of small-molecule phenotypic screens on drug discovery as well as on the investigation of human development and disease biology. We further examine the role of 3D spheroid/organoid structures, microfluidic systems, and miniaturized on-a-chip systems for future discovery strategies. In highlighting representative examples, we analyze how recent achievements can translate into future therapies. Finally, we discuss remaining challenges that need to be overcome for the adaptation of the next generation of screening approaches.
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Affiliation(s)
- Alexandra Friese
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Andrei Ursu
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany; Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458, USA; Faculty of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany
| | - Andreas Hochheimer
- ISAR Bioscience GmbH, Institute for Stem Cell & Applied Regenerative Medicine Research, 82152 Planegg, Germany
| | - Hans R Schöler
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany; Medical Faculty, University of Münster, Domagkstrasse 3, 48149 Münster, Germany.
| | - Herbert Waldmann
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany; Faculty of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany.
| | - Jan M Bruder
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany.
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46
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Li C, Niles DJ, Juang DS, Lang JM, Beebe DJ. Automated System for Small-Population Single-Particle Processing Enabled by Exclusive Liquid Repellency. SLAS Technol 2019; 24:535-542. [PMID: 31180792 DOI: 10.1177/2472630319853219] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Exclusive liquid repellency (ELR) describes an extreme wettability phenomenon in which a liquid phase droplet is completely repelled from a solid phase when exposed to a secondary immiscible liquid phase. Earlier, we developed a multi-liquid-phase open microfluidic (or underoil) system based on ELR to facilitate rare-cell culture and single-cell processing. The ELR system can allow for the handling of small volumes of liquid droplets with ultra-low sample loss and biofouling, which makes it an attractive platform for biological applications that require lossless manipulation of rare cellular samples (especially for a limited sample size in the range of a few hundred to a few thousand cells). Here, we report an automated platform using ELR microdrops for single-particle (or single-cell) isolation, identification, and retrieval. This was accomplished via the combined use of a robotic liquid handler, an automated microscopic imaging system, and real-time image-processing software for single-particle identification. The automated ELR technique enables rapid, hands-free, and robust isolation of microdrop-encapsulated rare cellular samples.
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Affiliation(s)
- Chao Li
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - David J Niles
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Duane S Juang
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Joshua M Lang
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA.,Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI, USA
| | - David J Beebe
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA.,Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI, USA.,Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, USA
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47
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Soitu C, Feuerborn A, Deroy C, Castrejón-Pita AA, Cook PR, Walsh EJ. Raising fluid walls around living cells. SCIENCE ADVANCES 2019; 5:eaav8002. [PMID: 31183401 PMCID: PMC6551168 DOI: 10.1126/sciadv.aav8002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Accepted: 04/29/2019] [Indexed: 05/04/2023]
Abstract
An effective transformation of the cell culture dishes that biologists use every day into microfluidic devices would open many avenues for miniaturizing cell-based workflows. In this article, we report a simple method for creating microfluidic arrangements around cells already growing on the surface of standard petri dishes, using the interface between immiscible fluids as a "building material." Conventional dishes are repurposed into sophisticated microfluidic devices by reshaping, on demand, the fluid structures around living cells. Moreover, these microfluidic arrangements can be further reconfigured during experiments, which is impossible with most existing microfluidic platforms. The method is demonstrated using workflows involving cell cloning, the selection of a particular clone from among others in a dish, drug treatments, and wound healing. The versatility of the approach and its biologically friendly aspects may hasten uptake by biologists of microfluidics, so the technology finally fulfills its potential.
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Affiliation(s)
- Cristian Soitu
- Oxford Thermofluids Institute, Department of Engineering Science, University of Oxford, Osney Mead, Oxford OX2 0ES, UK
| | - Alexander Feuerborn
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
- Iota Sciences Ltd., Begbroke Science Park, Begbroke, Oxfordshire OX5 1PF, UK
| | - Cyril Deroy
- Oxford Thermofluids Institute, Department of Engineering Science, University of Oxford, Osney Mead, Oxford OX2 0ES, UK
| | | | - Peter R. Cook
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Edmond J. Walsh
- Oxford Thermofluids Institute, Department of Engineering Science, University of Oxford, Osney Mead, Oxford OX2 0ES, UK
- Iota Sciences Ltd., Begbroke Science Park, Begbroke, Oxfordshire OX5 1PF, UK
- Corresponding author.
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48
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Wu Z, Cai H, Ao Z, Nunez A, Liu H, Bondesson M, Guo S, Guo F. A Digital Acoustofluidic Pump Powered by Localized Fluid-Substrate Interactions. Anal Chem 2019; 91:7097-7103. [PMID: 31083981 DOI: 10.1021/acs.analchem.9b00069] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The precise transportation of small-volume liquids in microfluidic and nanofluidic systems remains a challenge for many applications, such as clinical fluidical analysis. Here, we present a reliable digital pump that utilizes acoustic streaming induced by localized fluid-substrate interactions. By locally generating streaming via a C-shaped interdigital transducer (IDT) within a triangle-edged microchannel, our acoustofluidic pump can generate a stable unidirectional flow (∼nanoliter per second flow rate) with a precise digital regulation (∼second response time), and it is capable of handling aqueous solutions (e.g., PBS buffer) as well as high viscosity liquids (e.g., human blood) with a nanoliter-scale volume. Along with our acoustofluidic pump's low cost, programmability, and capacity to control small-volumes at high precision, it could be widely used for point-of-care diagnostics, precise drug delivery, and fundamental biomedical research.
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Affiliation(s)
- Zhuhao Wu
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology , Wuhan University , Wuhan 430072 , China.,Department of Intelligent Systems Engineering , Indiana University , Bloomington , Indiana 47405 , United States
| | - Hongwei Cai
- Department of Intelligent Systems Engineering , Indiana University , Bloomington , Indiana 47405 , United States
| | - Zheng Ao
- Department of Intelligent Systems Engineering , Indiana University , Bloomington , Indiana 47405 , United States
| | - Asael Nunez
- Department of Intelligent Systems Engineering , Indiana University , Bloomington , Indiana 47405 , United States
| | - Hongcheng Liu
- Department of Industrial and Systems Engineering , University of Florida , Gainesville , Florida 32611 , United States
| | - Maria Bondesson
- Department of Intelligent Systems Engineering , Indiana University , Bloomington , Indiana 47405 , United States
| | - Shishang Guo
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology , Wuhan University , Wuhan 430072 , China
| | - Feng Guo
- Department of Intelligent Systems Engineering , Indiana University , Bloomington , Indiana 47405 , United States
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49
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Loo JFC, Ho AHP, Turner APF, Mak WC. Integrated Printed Microfluidic Biosensors. Trends Biotechnol 2019; 37:1104-1120. [PMID: 30992149 DOI: 10.1016/j.tibtech.2019.03.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/07/2019] [Accepted: 03/07/2019] [Indexed: 02/07/2023]
Abstract
Integrated printed microfluidic biosensors are one of the most recent point-of-care (POC) sensor developments. Fast turnaround time for production and ease of customization, enabled by the integration of recognition elements and transducers, are key for on-site biosensing for both healthcare and industry and for speeding up translation to real-life applications. Here, we provide an overview of recent progress in printed microfluidics, from the 2D to the 4D level, accompanied by novel sensing element integration. We also explore the latest trends in integrated printed microfluidics for healthcare, especially POC diagnostics, and food safety applications.
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Affiliation(s)
- Jacky F C Loo
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong Special Administrative Region
| | - Aaron H P Ho
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong Special Administrative Region
| | | | - Wing Cheung Mak
- Biosensors and Bioelectronics Centre, Department of Physics, Chemistry and Biology (IFM), Linköping University, 58183, Linköping, Sweden.
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Pickering M, Hollis LN, D'Souza E, Rhind N. Fission yeast cells grow approximately exponentially. Cell Cycle 2019; 18:869-879. [PMID: 30957637 DOI: 10.1080/15384101.2019.1595874] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
How the rate of cell growth is influenced by cell size is a fundamental question of cell biology. The simple model that cell growth is proportional to cell size, based on the proposition that larger cells have proportionally greater synthetic capacity than smaller cells, leads to the prediction that the rate of cell growth increases exponentially with cell size. However, other modes of cell growth, including bilinear growth, have been reported. The distinction between exponential and bilinear growth has been explored in particular detail in the fission yeast Schizosaccharomyces pombe. We have revisited the mode of fission yeast cell growth using high-resolution time-lapse microscopy and find, as previously reported, that these two growth models are difficult to distinguish both because of the similarity in shapes between exponential and bilinear curves over the two-fold change in length of a normal cell cycle and because of the substantial biological and experimental noise inherent to these experiments. Therefore, we contrived to have cells grow more than twofold, by holding them in G2 for up to 8 h. Over this extended growth period, in which cells grow up to 5.5-fold, the two growth models diverge to the point that we can confidently exclude bilinear growth as a general model for fission yeast growth. Although the growth we observe is clearly more complicated than predicted by simple exponential growth, we find that exponential growth is a robust approximation of fission yeast growth, both during an unperturbed cell cycle and during extended periods of growth.
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Affiliation(s)
- Mary Pickering
- a Biochemistry and Molecular Pharmacology , University of Massachusetts Medical School , Worcester , MA , USA
| | - Lauren Nicole Hollis
- a Biochemistry and Molecular Pharmacology , University of Massachusetts Medical School , Worcester , MA , USA
| | - Edridge D'Souza
- a Biochemistry and Molecular Pharmacology , University of Massachusetts Medical School , Worcester , MA , USA
| | - Nicholas Rhind
- a Biochemistry and Molecular Pharmacology , University of Massachusetts Medical School , Worcester , MA , USA
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