1
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Haley JA, Chalasani SH. C. elegans foraging as a model for understanding the neuronal basis of decision-making. Cell Mol Life Sci 2024; 81:252. [PMID: 38849591 PMCID: PMC11335288 DOI: 10.1007/s00018-024-05223-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 03/27/2024] [Accepted: 03/30/2024] [Indexed: 06/09/2024]
Abstract
Animals have evolved to seek, select, and exploit food sources in their environment. Collectively termed foraging, these ubiquitous behaviors are necessary for animal survival. As a foundation for understanding foraging, behavioral ecologists established early theoretical and mathematical frameworks which have been subsequently refined and supported by field and laboratory studies of foraging animals. These simple models sought to explain how animals decide which strategies to employ when locating food, what food items to consume, and when to explore the environment for new food sources. These foraging decisions involve integration of prior experience with multimodal sensory information about the animal's current environment and internal state. We suggest that the nematode Caenorhabditis elegans is well-suited for a high-resolution analysis of complex goal-oriented behaviors such as foraging. We focus our discussion on behavioral studies highlighting C. elegans foraging on bacteria and summarize what is known about the underlying neuronal and molecular pathways. Broadly, we suggest that this simple model system can provide a mechanistic understanding of decision-making and present additional avenues for advancing our understanding of complex behavioral processes.
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Affiliation(s)
- Jessica A Haley
- Neurosciences Graduate Program, University of California San Diego, La Jolla, CA, 92093, USA
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Sreekanth H Chalasani
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA.
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2
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Banse SA, Jarrett CM, Robinson KJ, Blue BW, Shaw EL, Phillips PC. The egg-counter: a novel microfluidic platform for characterization of Caenorhabditis elegans egg-laying. LAB ON A CHIP 2024; 24:2975-2986. [PMID: 38738514 PMCID: PMC11131562 DOI: 10.1039/d3lc01073b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 04/20/2024] [Indexed: 05/14/2024]
Abstract
Reproduction is a fundamental process that shapes the demography of every living organism yet is often difficult to assess with high precision in animals that produce large numbers of offspring. Here, we present a novel microfluidic research platform for studying Caenorhabditis elegans' egg-laying. The platform provides higher throughput than traditional solid-media behavioral assays while providing a very high degree of temporal resolution. Additionally, the environmental control enabled by microfluidic animal husbandry allows for experimental perturbations difficult to achieve with solid-media assays. We demonstrate the platform's utility by characterizing C. elegans egg-laying behavior at two commonly used temperatures, 15 and 20 °C. As expected, we observed a delayed onset of egg-laying at 15 °C degrees, consistent with published temperature effects on development rate. Additionally, as seen in solid media studies, egg laying output was higher under the canonical 20 °C conditions. While we validated the Egg-Counter with a study of temperature effects in wild-type animals, the platform is highly adaptable to any nematode egg-laying research where throughput or environmental control needs to be maximized without sacrificing temporal resolution.
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Affiliation(s)
- Stephen A Banse
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA.
| | - Cody M Jarrett
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA.
| | - Kristin J Robinson
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA.
| | - Benjamin W Blue
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA.
| | - Emily L Shaw
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA.
| | - Patrick C Phillips
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA.
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3
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Dong K, Liu WC, Su Y, Lyu Y, Huang H, Zheng N, Rogers JA, Nan K. Scalable Electrophysiology of Millimeter-Scale Animals with Electrode Devices. BME FRONTIERS 2023; 4:0034. [PMID: 38435343 PMCID: PMC10907027 DOI: 10.34133/bmef.0034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 11/08/2023] [Indexed: 03/05/2024] Open
Abstract
Millimeter-scale animals such as Caenorhabditis elegans, Drosophila larvae, zebrafish, and bees serve as powerful model organisms in the fields of neurobiology and neuroethology. Various methods exist for recording large-scale electrophysiological signals from these animals. Existing approaches often lack, however, real-time, uninterrupted investigations due to their rigid constructs, geometric constraints, and mechanical mismatch in integration with soft organisms. The recent research establishes the foundations for 3-dimensional flexible bioelectronic interfaces that incorporate microfabricated components and nanoelectronic function with adjustable mechanical properties and multidimensional variability, offering unique capabilities for chronic, stable interrogation and stimulation of millimeter-scale animals and miniature tissue constructs. This review summarizes the most advanced technologies for electrophysiological studies, based on methods of 3-dimensional flexible bioelectronics. A concluding section addresses the challenges of these devices in achieving freestanding, robust, and multifunctional biointerfaces.
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Affiliation(s)
- Kairu Dong
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- National Key Laboratory of Advanced Drug Delivery and Release Systems,
Zhejiang University, Hangzhou 310058, China
- College of Biomedical Engineering & Instrument Science,
Zhejiang University, Hangzhou, 310027, China
| | - Wen-Che Liu
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- National Key Laboratory of Advanced Drug Delivery and Release Systems,
Zhejiang University, Hangzhou 310058, China
| | - Yuyan Su
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- Department of Gastroenterology, Brigham and Women’s Hospital,
Harvard Medical School, Boston, MA 02115, USA
| | - Yidan Lyu
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
| | - Hao Huang
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- College of Chemical and Biological Engineering,
Zhejiang University, Hangzhou 310058, China
| | - Nenggan Zheng
- Qiushi Academy for Advanced Studies,
Zhejiang University, Hangzhou 310027, China
- College of Computer Science and Technology,
Zhejiang University, Hangzhou 310027, China
- State Key Lab of Brain-Machine Intelligence,
Zhejiang University, Hangzhou 310058, China
- CCAI by MOE and Zhejiang Provincial Government (ZJU), Hangzhou 310027, China
| | - John A. Rogers
- Querrey Simpson Institute for Bioelectronics,
Northwestern University, Evanston, IL 60208, USA
- Department of Biomedical Engineering,
Northwestern University, Evanston, IL 60208, USA
- Department of Materials Science and Engineering,
Northwestern University, Evanston, IL 60208, USA
- Department of Mechanical Engineering,
Northwestern University, Evanston, IL 60208, USA
| | - Kewang Nan
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- National Key Laboratory of Advanced Drug Delivery and Release Systems,
Zhejiang University, Hangzhou 310058, China
- Jinhua Institute of Zhejiang University, Jinhua 321299, China
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4
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Banse SA, Jarrett CM, Robinson KJ, Blue BW, Shaw EL, Phillips PC. The Egg-Counter: A novel microfluidic platform for characterization of Caenorhabditis elegans egg-laying. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.01.555781. [PMID: 37732270 PMCID: PMC10508723 DOI: 10.1101/2023.09.01.555781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Reproduction is a fundamental process that shapes the demography of every living organism yet is often difficult to assess with high precision in animals that produce large numbers of offspring. Here, we present a novel microfluidic research platform for studying Caenorhabditis elegans' egg-laying. The platform provides higher throughput than traditional solid-media assays while providing a very high degree of temporal resolution. Additionally, the environmental control enabled by microfluidic animal husbandry allows for experimental perturbations difficult to achieve with solid-media assays. We demonstrate the platform's utility by characterizing C. elegans egg-laying behavior at two commonly used temperatures, 15 and 20°C. As expected, we observed a delayed onset of egg-laying at 15°C degrees, consistent with published temperature effects on development rate. Additionally, as seen in solid media studies, egg laying output was higher under the canonical 20°C conditions. While we validated the Egg-Counter with a study of temperature effects in wild-type animals, the platform is highly adaptable to any nematode egg-laying research where throughput or environmental control needs to be maximized without sacrificing temporal resolution.
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Affiliation(s)
- Stephen A. Banse
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Cody M. Jarrett
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Kristin J. Robinson
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Benjamin W. Blue
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Emily L. Shaw
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Patrick C. Phillips
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
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5
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Rezaeianaran F, Gijs MAM. Difference in Intestine Content of Caenorhabditis elegans When Fed on Non-Pathogenic or Pathogenic Bacteria. MICROMACHINES 2023; 14:1386. [PMID: 37512697 PMCID: PMC10384281 DOI: 10.3390/mi14071386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/30/2023] [Accepted: 07/05/2023] [Indexed: 07/30/2023]
Abstract
We investigated the bacterial food digestion and accumulation in wild-type adult Caenorhabditis elegans (C. elegans) worms that have fed on either non-pathogenic RFP-expressing Escherichia coli (E. coli) OP50 or pathogenic-RFP-expressing Pseudomonas aeruginosa (P. aeruginosa) PAO1 during the first 4 days of adulthood. Once the worms had completed their planned feeding cycles, they were loaded on microfluidic chips, where they were fixed to allow high-resolution z-stack fluorescence imaging of their intestines utilizing a Spinning Disk Confocal Microscope (SDCM) equipped with a high-resolution oil-immersion objective (60×). IMARIS software was used to visualize and analyze the obtained images, resulting in the production of three-dimensional constructs of the intestinal bacterial load. We discovered two distinct patterns for the bacteria-derived fluorescence signal in the intestine: (i) individual fluorescent spots, originating from intact bacteria, were present in the fluorescent E. coli-OP50-fed worms, and (ii) individual fluorescent spots (originating from intact bacteria) were dispersed in large regions of diffuse fluorescence (RDF), originating from disrupted bacteria, in fluorescent P. aeruginosa-PAO1-fed worms. We performed a semi-automated single-worm-resolution quantitative analysis of the intestinal bacterial load, which showed that the intestinal bacterial load generally increases with age of the worms, but more rapidly for the fluorescent P. aeruginosa-PAO1-fed worms.
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Affiliation(s)
- Farzad Rezaeianaran
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Martin A M Gijs
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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6
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Rezaeianaran F, Gijs MAM. High-resolution imaging and analysis of the intestinal bacterial load of Caenorhabditis elegans during early adulthood. RSC Adv 2023; 13:17230-17243. [PMID: 37304789 PMCID: PMC10248764 DOI: 10.1039/d3ra02934d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 05/31/2023] [Indexed: 06/13/2023] Open
Abstract
We study the presence within the worm Caenorhabditis elegans (C. elegans) of a fluorescent strain of the worm's bacterial food (Escherichia coli (E. coli) OP50) during early adulthood. Use of a microfluidic chip based on a thin glass coverslip substrate allows investigation of the intestinal bacterial load using a Spinning Disk Confocal Microscope (SDCM) equipped with a high-resolution objective (60×). High-resolution z-stack fluorescence images of the gut bacteria in adult worms, which were loaded in the microfluidic chip and subsequently fixed, were analyzed using IMARIS software and 3D reconstructions of the intestinal bacterial load in the worms were obtained. We present an automated bivariate histogram analysis of the volumes and intensities of the bacterial spots for each worm and find that, as the worms age, the bacterial load in their hindguts increases. We show the advantage of single-worm resolution automated analysis for bacterial load studies and anticipate that the methods described in our work can be easily implemented in existing microfluidic solutions to enable thorough studies of bacterial proliferation.
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Affiliation(s)
- Farzad Rezaeianaran
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne CH-1015 Lausanne Switzerland
| | - Martin A M Gijs
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne CH-1015 Lausanne Switzerland
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7
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Sanfeliu-Cerdán N, Lin LC, Dunn AR, Goodman MB, Krieg M. Visualizing Neurons Under Tension In Vivo with Optogenetic Molecular Force Sensors. Methods Mol Biol 2023; 2600:239-266. [PMID: 36587102 DOI: 10.1007/978-1-0716-2851-5_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The visualization of mechanical stress distribution in specific molecular networks within a living and physiologically active cell or animal remains a formidable challenge in mechanobiology. The advent of fluorescence-resonance energy transfer (FRET)-based molecular tension sensors overcame a significant hurdle that now enables us to address previously technically limited questions. Here, we describe a method that uses genetically encoded FRET tension sensors to visualize the mechanics of cytoskeletal networks in neurons of living animals with sensitized emission FRET and confocal scanning light microscopy. This method uses noninvasive immobilization of living animals to image neuronal β-spectrin cytoskeleton at the diffraction limit, and leverages multiple imaging controls to verify and underline the quality of the measurements. In combination with a semiautomated machine-vision algorithm to identify and trace individual neurites, our analysis performs simultaneous calculation of FRET efficiencies and visualizes statistical uncertainty on a pixel by pixel basis. Our approach is not limited to genetically encoded spectrin tension sensors, but can also be used for any kind of ratiometric imaging in neuronal cells both in vivo and in vitro.
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Affiliation(s)
- Neus Sanfeliu-Cerdán
- Neurophotonics and Mechanical Systems Biology, ICFO, Institut de Ciències Fotòniques, ICFO, Castelldefels, Spain
| | - Li-Chun Lin
- Neurophotonics and Mechanical Systems Biology, ICFO, Institut de Ciències Fotòniques, ICFO, Castelldefels, Spain
| | - Alexander R Dunn
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Miriam B Goodman
- Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
| | - Michael Krieg
- Neurophotonics and Mechanical Systems Biology, ICFO, Institut de Ciències Fotòniques, ICFO, Castelldefels, Spain.
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8
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Quintin S, Aspert T, Ye T, Charvin G. Distinct mechanisms underlie H2O2 sensing in C. elegans head and tail. PLoS One 2022; 17:e0274226. [PMID: 36173997 PMCID: PMC9521893 DOI: 10.1371/journal.pone.0274226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 08/23/2022] [Indexed: 12/29/2022] Open
Abstract
Environmental oxidative stress threatens cellular integrity and should therefore be avoided by living organisms. Yet, relatively little is known about environmental oxidative stress perception. Here, using microfluidics, we showed that like I2 pharyngeal neurons, the tail phasmid PHA neurons function as oxidative stress sensing neurons in C. elegans, but display different responses to H2O2 and light. We uncovered that different but related receptors, GUR-3 and LITE-1, mediate H2O2 signaling in I2 and PHA neurons. Still, the peroxiredoxin PRDX-2 is essential for both, and might promote H2O2-mediated receptor activation. Our work demonstrates that C. elegans can sense a broad range of oxidative stressors using partially distinct H2O2 signaling pathways in head and tail sensillae, and paves the way for further understanding of how the integration of these inputs translates into the appropriate behavior.
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Affiliation(s)
- Sophie Quintin
- Department of Developmental Biology and Stem Cells, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Théo Aspert
- Department of Developmental Biology and Stem Cells, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Tao Ye
- Department of Developmental Biology and Stem Cells, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Gilles Charvin
- Department of Developmental Biology and Stem Cells, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
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9
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Aubry G, Milisavljevic M, Lu H. Automated and Dynamic Control of Chemical Content in Droplets for Scalable Screens of Small Animals. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2200319. [PMID: 35229457 PMCID: PMC9050880 DOI: 10.1002/smll.202200319] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Indexed: 06/14/2023]
Abstract
Screening functional phenotypes in small animals is important for genetics and drug discovery. Multiphase microfluidics has great potential for enhancing throughput but has been hampered by inefficient animal encapsulation and limited control over the animal's environment in droplets. Here, a highly efficient single-animal encapsulation unit, a liquid exchanger system for controlling the droplet chemical environment dynamically, and an automation scheme for the programming and robust execution of complex protocols are demonstrated. By careful use of interfacial forces, the liquid exchanger unit allows for adding and removing chemicals from a droplet and, therefore, generating chemical gradients inaccessible in previous multiphase systems. Using Caenorhabditis elegans as an example, it is demonstrated that these advances can serve to analyze dynamic phenotyping, such as behavior and neuronal activity, perform forward genetic screen, and are scalable to manipulate animals of different sizes. This platform paves the way for large-scale screens of complex dynamic phenotypes in small animals.
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Affiliation(s)
- Guillaume Aubry
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Marija Milisavljevic
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Hang Lu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
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10
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Youssef K, Archonta D, Kubiseski TJ, Tandon A, Rezai P. Microfluidic electric parallel egg-laying assay and application to in-vivo toxicity screening of microplastics using C. elegans. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 783:147055. [PMID: 34088132 DOI: 10.1016/j.scitotenv.2021.147055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/26/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
Environmental pollutants like microplastics are posing health concerns on aquatic animals and the ecosystem. Microplastic toxicity studies using Caenorhabditis elegans (C. elegans) as a model are evolving but methodologically hindered from obtaining statistically strong data sets, detecting toxicity effects based on microplastics uptake, and correlating physiological and behavioural effects at an individual-worm level. In this paper, we report a novel microfluidic electric egg-laying assay for phenotypical assessment of multiple worms in parallel. The effects of glucose and polystyrene microplastics at two concentrations on the worms' electric egg-laying, length, diameter, and length contraction during exposure to electric signal were studied. The device contained eight parallel worm-dwelling microchannels called electric traps, with equivalent electrical fields, in which the worms were electrically stimulated for egg deposition and fluorescently imaged for assessment of neuronal and microplastic uptake expression. A new bidirectional stimulation technique was developed, and the device design was optimized to achieve a testing efficiency of 91.25%. Exposure of worms to 100 mM glucose resulted in a significant reduction in their egg-laying and size. The effects of 1 μm polystyrene microparticles at concentrations of 100 and 1000 mg/L on the electric egg-laying behaviour, size, and neurodegeneration of N2 and NW1229 (expressing GFP pan-neuronally) worms were also studied. Of the two concentrations, 1000 mg/L caused severe egg-laying deficiency and growth retardation as well as neurodegeneration. Additionally, using single-worm level phenotyping, we noticed intra-population variability in microplastics uptake and correlation with the above physiological and behavioural phenotypes, which was hidden in the population-averaged results. Taken together, these results suggest the appropriateness of our microfluidic assay for toxicological studies and for assessing the phenotypical heterogeneity in response to microplastics.
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Affiliation(s)
- Khaled Youssef
- Department of Mechanical Engineering, York University, Toronto, ON, Canada
| | - Daphne Archonta
- Department of Mechanical Engineering, York University, Toronto, ON, Canada
| | | | - Anurag Tandon
- Tanz Centre for Research in Neurodegenerative Diseases, Toronto, Ontario, Canada; Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Pouya Rezai
- Department of Mechanical Engineering, York University, Toronto, ON, Canada.
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11
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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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12
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Viri V, Arveiler M, Lehnert T, Gijs MAM. An In Vivo Microfluidic Study of Bacterial Load Dynamics and Absorption in the C. elegans Intestine. MICROMACHINES 2021; 12:832. [PMID: 34357242 PMCID: PMC8304684 DOI: 10.3390/mi12070832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/13/2021] [Accepted: 07/15/2021] [Indexed: 01/19/2023]
Abstract
Caenorhabditiselegans (C. elegans) has gained importance as a model for studying host-microbiota interactions and bacterial infections related to human pathogens. Assessing the fate of ingested bacteria in the worm's intestine is therefore of great interest, in particular with respect to normal bacterial digestion or intestinal colonization by pathogens. Here, we report an in vivo study of bacteria in the gut of C. elegans. We take advantage of a polydimethylsiloxane (PDMS) microfluidic device enabling passive immobilization of adult worms under physiological conditions. Non-pathogenic Escherichia coli (E. coli) bacteria expressing either pH-sensitive or pH-insensitive fluorescence reporters as well as fluorescently marked indigestible microbeads were used for the different assays. Dynamic fluorescence patterns of the bacterial load in the worm gut were conveniently monitored by time-lapse imaging. Cyclic motion of the bacterial load due to peristaltic activity of the gut was observed and biochemical digestion of E. coli was characterized by high-resolution fluorescence imaging of the worm's intestine. We could discriminate between individual intact bacteria and diffuse signals related to disrupted bacteria that can be digested. From the decay of the diffuse fluorescent signal, we determined a digestion time constant of 14 ± 4 s. In order to evaluate the possibility to perform infection assays with our platform, immobilized C. elegans worms were fed pathogenic Mycobacterium marinum (M. marinum) bacteria. We analyzed bacterial fate and accumulation in the gut of N2 worms and mitochondrial stress response in a hsp-6::gfp mutant.
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Affiliation(s)
| | | | | | - Martin A. M. Gijs
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland; (V.V.); (M.A.); (T.L.)
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13
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Neuroscience Research using Small Animals on a Chip: From Nematodes to Zebrafish Larvae. BIOCHIP JOURNAL 2021. [DOI: 10.1007/s13206-021-00012-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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14
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Abstract
In the last decade, microfluidic methods have proven to be powerful tools for Caenorhabditis elegans research, offering advanced manipulation of worms and precise control of experimental conditions. The advantages of microfluidic chips include their capability of immobilization, automated sorting, and longitudinal measurement, and more. In this review, we focus on control components that are widely used in the design of microfluidic devices, and discuss their functions and working principles that enable advanced manipulation on a chip. Understanding these components will ease the onboarding of researchers inexperienced with microfluidics and help them bring the power of microfluidics to new applications.
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Affiliation(s)
- Erel Levine
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | - Kyung Suk Lee
- Department of Physics Education, Kongju National University, Gongju, South Korea
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15
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Rahman M, Edwards H, Birze N, Gabrilska R, Rumbaugh KP, Blawzdziewicz J, Szewczyk NJ, Driscoll M, Vanapalli SA. NemaLife chip: a micropillar-based microfluidic culture device optimized for aging studies in crawling C. elegans. Sci Rep 2020; 10:16190. [PMID: 33004810 PMCID: PMC7530743 DOI: 10.1038/s41598-020-73002-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 09/10/2020] [Indexed: 01/23/2023] Open
Abstract
In this study, we report a microfluidic device for the whole-life culture of the nematode Caenorhabditis elegans that allows the scoring of animal survival and health measures. This device referred to as the NemaLife chip features: (1) an optimized micropillar arena in which animals can crawl, (2) sieve channels that separate progeny and prevent the loss of adults from the arena during culture maintenance, and (3) ports that allow rapid accessibility for feeding the adult-only population and introducing reagents as needed. The pillar arena geometry was optimized to accommodate the growing body size during culture and emulate the body gait and locomotion of animals reared on agar. Likewise, feeding protocols were optimized to recapitulate longevity outcomes typical of standard plate growth. Key benefits of the NemaLife Chip include eliminating the need to perform repeated manual transfers of adults during survival assays, negating the need for progeny-blocking chemical interventions, and avoiding the swim-induced stress across lifespan in animals reared in liquid. We also show that the culture of animals in pillar-less microfluidic chambers reduces lifespan and introduces physiological stress by increasing the occurrence of age-related vulval integrity disorder. We validated our pillar-based device with longevity analyses of classical aging mutants (daf-2, age-1, eat-2, and daf-16) and animals subjected to RNAi knockdown of age-related genes (age-1 and daf-16). We also showed that healthspan measures such as pharyngeal pumping and tap-induced stimulated reversals can be scored across the lifespan in the NemaLife chip. Overall, the capacity to generate reliable lifespan and physiological data underscores the potential of the NemaLife chip to accelerate healthspan and lifespan investigations in C. elegans.
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Affiliation(s)
- Mizanur Rahman
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - Hunter Edwards
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - Nikolajs Birze
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - Rebecca Gabrilska
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, 79409, USA
| | - Kendra P Rumbaugh
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, 79409, USA
| | - Jerzy Blawzdziewicz
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, 79430, USA
| | - Nathaniel J Szewczyk
- Ohio Musculoskeletal and Neurological Institute and Department of Biomedical Sciences, Ohio University, Athens, OH, 45701, USA
| | - Monica Driscoll
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ, 08854, USA
| | - Siva A Vanapalli
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, 79409, USA.
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16
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Viri V, Cornaglia M, Atakan HB, Lehnert T, Gijs MAM. An in vivo microfluidic study of bacterial transit in C. elegans nematodes. LAB ON A CHIP 2020; 20:2696-2708. [PMID: 32633746 DOI: 10.1039/d0lc00064g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Caenorhabditis elegans (C. elegans) constitutes an important model organism for use in nutrition and aging studies. We report a novel method for studying the dynamics of Escherichia coli (E. coli) bacterial transit through the worms' intestine. A microfluidic chip was designed for alternating C. elegans on-chip culture and immobilization, thereby enabling periodic high-resolution time-lapse imaging at single-worm resolution over several days. Immobilization was achieved in a reversible way using arrays of tapered channels suitable for assay parallelization. Dedicated C. elegans feeding protocols were applied. Two E. coli bacterial strains, HT115 and OP50, respectively labeled with green fluorescent protein (GFP) and red fluorescent protein (RFP), were used as food source and imaged with fluorescence microscopy techniques to measure relevant parameters of the bacterial transit process. Feeding behavior and E. coli transit dynamics in the whole intestinal tract of the worms were characterized in an automated way over the first 3 days of adulthood, revealing both fast transit phenomena and variations in microbial accumulation. In particular, we studied the bacterial food transit periodicity in wild-type and eat-2 (ad465) mutant C. elegans strains in both trapped and free-swimming conditions. In order to further demonstrate the versatility of our microfluidic platform, we also studied drug-induced modifications of the bacterial transit by measuring the response of the worms' intestine to exposure to the neurotransmitter serotonin.
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Affiliation(s)
- Vittorio Viri
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
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17
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Gonzales DL, Badhiwala KN, Avants BW, Robinson JT. Bioelectronics for Millimeter-Sized Model Organisms. iScience 2020; 23:100917. [PMID: 32114383 PMCID: PMC7049667 DOI: 10.1016/j.isci.2020.100917] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/29/2020] [Accepted: 02/10/2020] [Indexed: 01/27/2023] Open
Abstract
Advances in microfabrication technologies and biomaterials have enabled a growing class of electronic devices that can stimulate and record bioelectronic signals. Many of these devices have been developed for humans or vertebrate animals, where miniaturization allows for implantation within the body. There are, however, another class of bioelectronic interfaces that exploit microfabrication and nanoelectronics to record signals from tiny, millimeter-sized organisms. In these cases, rather than implanting a device inside an animal, animals themselves are loaded in large numbers into bioelectronic devices for neural circuit and behavioral interrogation. These scalable interfaces provide platforms to develop new therapeutics as well as better understand basic principles of bioelectronic communication, neuroscience, and behavior. Here we review recent progress in these bioelectronic technologies and describe how they can complement on-chip optical, mechanical, and chemical interrogation methods to achieve high-throughput, multimodal studies of millimeter-sized small animals.
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Affiliation(s)
- Daniel L Gonzales
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Dr., West Lafayette, IN 47907, USA
| | - Krishna N Badhiwala
- Department of Bioengineering, Rice University, 6100 Main St., Houston, TX 77005, USA
| | - Benjamin W Avants
- Department of Electrical and Computer Engineering, Rice University, 6100 Main St., Houston, TX 77005, USA
| | - Jacob T Robinson
- Department of Bioengineering, Rice University, 6100 Main St., Houston, TX 77005, USA; Department of Electrical and Computer Engineering, Rice University, 6100 Main St., Houston, TX 77005, USA; Applied Physics Program, Rice University, 6100 Main St., Houston, TX 77005, USA; Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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18
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Gonzales DL, Zhou J, Fan B, Robinson JT. A microfluidic-induced C. elegans sleep state. Nat Commun 2019; 10:5035. [PMID: 31695031 PMCID: PMC6834590 DOI: 10.1038/s41467-019-13008-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 10/02/2019] [Indexed: 01/01/2023] Open
Abstract
An important feature of animal behavior is the ability to switch rapidly between activity states, however, how the brain regulates these spontaneous transitions based on the animal's perceived environment is not well understood. Here we show a C. elegans sleep-like state on a scalable platform that enables simultaneous control of multiple environmental factors including temperature, mechanical stress, and food availability. This brief quiescent state, which we refer to as microfluidic-induced sleep, occurs spontaneously in microfluidic chambers, which allows us to track animal movement and perform whole-brain imaging. With these capabilities, we establish that microfluidic-induced sleep meets the behavioral requirements of C. elegans sleep and depends on multiple factors, such as satiety and temperature. Additionally, we show that C. elegans sleep can be induced through mechanosensory pathways. Together, these results establish a model system for studying how animals process multiple sensory pathways to regulate behavioral states.
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Affiliation(s)
- Daniel L Gonzales
- Applied Physics Program, Rice University, 6100 Main St., Houston, TX, 77005, USA
- Department of Electrical and Computer Engineering, Rice University, 6100 Main St., Houston, TX, 77005, USA
| | - Jasmine Zhou
- Department of Bioengineering, Rice University, 6100 Main St., Houston, TX, 77005, USA
| | - Bo Fan
- Department of Electrical and Computer Engineering, Rice University, 6100 Main St., Houston, TX, 77005, USA
| | - Jacob T Robinson
- Applied Physics Program, Rice University, 6100 Main St., Houston, TX, 77005, USA.
- Department of Electrical and Computer Engineering, Rice University, 6100 Main St., Houston, TX, 77005, USA.
- Department of Bioengineering, Rice University, 6100 Main St., Houston, TX, 77005, USA.
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
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19
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Patel DS, Xu N, Lu H. Digging deeper: methodologies for high-content phenotyping in Caenorhabditis elegans. Lab Anim (NY) 2019; 48:207-216. [PMID: 31217565 DOI: 10.1038/s41684-019-0326-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 05/17/2019] [Indexed: 11/09/2022]
Abstract
Deep phenotyping is an emerging conceptual paradigm and experimental approach aimed at measuring and linking many aspects of a phenotype to understand its underlying biology. To date, deep phenotyping has been applied mostly in cultured cells and used less in multicellular organisms. However, in the past decade, it has increasingly been recognized that deep phenotyping could lead to a better understanding of how genetics, environment and stochasticity affect the development, physiology and behavior of an organism. The nematode Caenorhabditis elegans is an invaluable model system for studying how genes affect a phenotypic trait, and new technologies have taken advantage of the worm's physical attributes to increase the throughput and informational content of experiments. Coupling of these technical advancements with computational and analytical tools has enabled a boom in deep-phenotyping studies of C. elegans. In this Review, we highlight how these new technologies and tools are digging into the biological origins of complex, multidimensional phenotypes.
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Affiliation(s)
- Dhaval S Patel
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Nan Xu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA.,The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Hang Lu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
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20
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Banse SA, Blue BW, Robinson KJ, Jarrett CM, Phillips PC. The Stress-Chip: A microfluidic platform for stress analysis in Caenorhabditis elegans. PLoS One 2019; 14:e0216283. [PMID: 31042764 PMCID: PMC6493750 DOI: 10.1371/journal.pone.0216283] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 04/17/2019] [Indexed: 02/01/2023] Open
Abstract
An organism's ability to mount a physiological response to external stressors is fundamental to its interaction with the environment. Experimental exploration of these interactions benefits greatly from the ability to maintain tight control of the environment, even under conditions in which it would be normal for the subject to flee the stressor. Here we present a nematode research platform that pairs automated image acquisition and analysis with a custom microfluidic device. This platform enables tight environmental control in low-density, single-worm arenas, which preclude animal escape while still allowing a broad range of behavioral activities. The platform is easily scalable, with two 50 arena arrays per chip and an imaging capacity of 600 animals per scanning device. Validating the device using dietary, osmotic, and oxidative stress indicates that it should be of broad use as a research platform, including eventual adaptation for additional stressors, anthelmintic-drug screening, and toxicology studies.
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Affiliation(s)
- Stephen A. Banse
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, United States of America
| | - Benjamin W. Blue
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, United States of America
| | - Kristin J. Robinson
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, United States of America
| | - Cody M. Jarrett
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, United States of America
| | - Patrick C. Phillips
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, United States of America
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21
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Breimann L, Preusser F, Preibisch S. Light-microscopy methods in C. elegans research. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.coisb.2018.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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22
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Affiliation(s)
- Gongchen Sun
- School of Chemical & Biomolecular Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - Hang Lu
- School of Chemical & Biomolecular Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
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23
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Kamili F, Lu H. Recent Advances and Trends in Microfluidic Platforms for C. elegans Biological Assays. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2018; 11:245-264. [PMID: 29894230 DOI: 10.1146/annurev-anchem-061417-125604] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Microfluidics has proven to be a key tool in quantitative biological research. The C. elegans research community in particular has developed a variety of microfluidic platforms to investigate sensory systems, development, aging, and physiology of the nematode. Critical for the growth of this field, however, has been the implementation of concurrent advanced microscopy, hardware, and software technologies that enable the discovery of novel biology. In this review, we highlight recent innovations in microfluidic platforms used for assaying C. elegans and discuss the novel technological approaches and analytic strategies required for these systems. We conclude that platforms that provide analytical frameworks for assaying specific biological mechanisms and those that take full advantage of integrated technologies to extract high-value quantitative information from worm assays are most likely to move the field forward.
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Affiliation(s)
- Farhan Kamili
- Interdisciplinary Program in Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Hang Lu
- Interdisciplinary Program in Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA;
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24
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Lee KS, Levine E. A Microfluidic Platform for Longitudinal Imaging in Caenorhabditis elegans. J Vis Exp 2018. [PMID: 29782012 DOI: 10.3791/57348] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In the last decade, microfluidic techniques have been applied to study small animals, including the nematode Caenorhabditis elegans, and have proved useful as a convenient live imaging platform providing capabilities for precise control of experimental conditions in real time. In this article, we demonstrate live imaging of individual worms employing WormSpa, a previously-published custom microfluidic device. In the device, multiple worms are individually confined to separate chambers, allowing multiplexed longitudinal surveillance of various biological processes. To illustrate the capability, we performed proof-of-principle experiments in which worms were infected in the device with pathogenic bacteria, and the dynamics of expression of immune response genes and egg laying were monitored continuously in individual animals. The simple design and operation of this device make it suitable for users with no previous experience with microfluidic-based experiments. We propose that this approach will be useful for many researchers interested in longitudinal observations of biological processes under well-defined conditions.
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Affiliation(s)
- Kyung Suk Lee
- Department of Physics Education, Kongju National University; Department of Physics, Harvard University
| | - Erel Levine
- Department of Physics, Harvard University; FAS Center for Systems Biology, Harvard University;
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25
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Berger S, Lattmann E, Aegerter-Wilmsen T, Hengartner M, Hajnal A, deMello A, Casadevall i Solvas X. Long-term C. elegans immobilization enables high resolution developmental studies in vivo. LAB ON A CHIP 2018; 18:1359-1368. [PMID: 29652050 DOI: 10.1039/c7lc01185g] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Live-imaging of C. elegans is essential for the study of conserved cellular pathways (e.g. EGFR/Wnt signaling) and morphogenesis in vivo. However, the usefulness of live imaging as a research tool has been severely limited by the need to immobilize worms prior to and during imaging. Conventionally, immobilization is achieved by employing both physical and chemical interventions. These are known to significantly affect many physiological processes, and thus limit our understanding of dynamic developmental processes. Herein we present a novel, easy-to-use microfluidic platform for the long-term immobilization of viable, normally developing C. elegans, compatible with image acquisition at high resolution, thereby overcoming the limitations associated with conventional worm immobilization. The capabilities of the platform are demonstrated through the continuous assessment of anchor cell (AC) invasion and distal tip cell (DTC) migration in larval C. elegans and germ cell apoptosis in adult C. elegans in vivo for the first time.
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Affiliation(s)
- Simon Berger
- Institute of Chemical and Bioengineering, ETH Zurich, 8093 Zurich, Switzerland.
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26
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Fehlauer H, Nekimken AL, Kim AA, Pruitt BL, Goodman MB, Krieg M. Using a Microfluidics Device for Mechanical Stimulation and High Resolution Imaging of C. elegans. J Vis Exp 2018. [PMID: 29553526 DOI: 10.3791/56530] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
One central goal of mechanobiology is to understand the reciprocal effect of mechanical stress on proteins and cells. Despite its importance, the influence of mechanical stress on cellular function is still poorly understood. In part, this knowledge gap exists because few tools enable simultaneous deformation of tissue and cells, imaging of cellular activity in live animals, and efficient restriction of motility in otherwise highly mobile model organisms, such as the nematode Caenorhabditis elegans. The small size of C. elegans makes them an excellent match to microfluidics-based research devices, and solutions for immobilization have been presented using microfluidic devices. Although these devices allow for high-resolution imaging, the animal is fully encased in polydimethylsiloxane (PDMS) and glass, limiting physical access for delivery of mechanical force or electrophysiological recordings. Recently, we created a device that integrates pneumatic actuators with a trapping design that is compatible with high-resolution fluorescence microscopy. The actuation channel is separated from the worm-trapping channel by a thin PDMS diaphragm. This diaphragm is deflected into the side of a worm by applying pressure from an external source. The device can target individual mechanosensitive neurons. The activation of these neurons is imaged at high-resolution with genetically-encoded calcium indicators. This article presents the general method using C. elegans strains expressing calcium-sensitive activity indicator (GCaMP6s) in their touch receptor neurons (TRNs). The method, however, is not limited to TRNs nor to calcium sensors as a probe, but can be expanded to other mechanically-sensitive cells or sensors.
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Affiliation(s)
- Holger Fehlauer
- Department of Molecular and Cellular Physiology, Stanford University
| | - Adam L Nekimken
- Department of Molecular and Cellular Physiology, Stanford University; Department of Mechanical Engineering, Stanford University
| | - Anna A Kim
- Department of Molecular and Cellular Physiology, Stanford University; Department of Mechanical Engineering, Stanford University
| | - Beth L Pruitt
- Department of Molecular and Cellular Physiology, Stanford University; Department of Mechanical Engineering, Stanford University; Department of Bioengineering, Stanford University;
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University; Department of Mechanical Engineering, Stanford University;
| | - Michael Krieg
- Group of Neurophotonics and Mechanical Systems Biology, The Institute of Photonic Sciences (ICFO);
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27
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Cornaglia M, Lehnert T, Gijs MAM. Microfluidic systems for high-throughput and high-content screening using the nematode Caenorhabditis elegans. LAB ON A CHIP 2017; 17:3736-3759. [PMID: 28840220 DOI: 10.1039/c7lc00509a] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In a typical high-throughput drug screening (HTS) process, up to millions of chemical compounds are applied to cells cultured in well plates, aiming to find molecules that exhibit a robust dose-response, as evidenced for example by a fluorescence signal. In high-content screening (HCS), one goes a step further by linking the tested compounds to phenotypic information, obtained, for instance, from microscopic cell images, thereby creating richer data sets that also require more advanced analysis methods. The nematode Caenorhabditis elegans came into the screening picture due to the wide availability of its mutants and human disease models, its relatively easy culture and short life cycle. Being a whole-organism model, it allows drug testing under physiological conditions at multi-tissue levels and provides additional observable phenotypes with respect to cell models, related, for instance, to development, aging, behavior or motility. Worm-based HTS studies in liquid environments on microwell plates have been demonstrated, while microfluidic devices allowed surpassing the performance of plates by enabling more versatile and accurate assays, precise and dynamic dosing of compounds, and readouts down to single-animal resolution. In this review, we discuss microfluidic devices for C. elegans analysis and related studies, published in the period from 2012 to 2017. After an introduction to the different screening approaches, we first focus on microfluidic systems with potential for screening applications. Various enabling technologies, e.g. electrophysiological on-chip recordings or laser axotomy, have been implemented, as well as techniques for reversible worm immobilization and high-resolution imaging, combined with algorithms for automated experimentation and analysis. Several devices for developmental or behavioral assays, and worm sorting based on different phenotypes, have been proposed too. In a subsequent section, we review the application of microfluidic-based systems for medium- and high-throughput screens, including neurobiology and neurodegeneration studies, aging and developmental assays, toxicity and pathogenesis screens, as well as behavioral and motility assays. A thorough analysis of this work reveals a trend towards microfluidic systems more and more capable of offering high-quality analyses of large worm populations, based on multi-phenotypic and/or longitudinal readouts, with clear potential for their application in larger HTS/HCS contexts.
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Affiliation(s)
- Matteo Cornaglia
- Laboratory of Microsystems, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland.
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28
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Sanders J, Scholz M, Merutka I, Biron D. Distinct unfolded protein responses mitigate or mediate effects of nonlethal deprivation of C. elegans sleep in different tissues. BMC Biol 2017; 15:67. [PMID: 28844202 PMCID: PMC5572162 DOI: 10.1186/s12915-017-0407-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 07/24/2017] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Disrupting sleep during development leads to lasting deficits in chordates and arthropods. To address lasting impacts of sleep deprivation in Caenorhabditis elegans, we established a nonlethal deprivation protocol. RESULTS Deprivation triggered protective insulin-like signaling and two unfolded protein responses (UPRs): the mitochondrial (UPRmt) and the endoplasmic reticulum (UPRER) responses. While the latter is known to be triggered by sleep deprivation in rodent and insect brains, the former was not strongly associated with sleep deprivation previously. We show that deprivation results in a feeding defect when the UPRmt is deficient and in UPRER-dependent germ cell apoptosis. In addition, when the UPRER is deficient, deprivation causes excess twitching in vulval muscles, mirroring a trend caused by loss of egg-laying command neurons. CONCLUSIONS These data show that nonlethal deprivation of C. elegans sleep causes proteotoxic stress. Unless mitigated, distinct types of deprivation-induced proteotoxicity can lead to anatomically and genetically separable lasting defects. The relative importance of different UPRs post-deprivation likely reflects functional, developmental, and genetic differences between the respective tissues and circuits.
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Affiliation(s)
- Jarred Sanders
- Genetics, Genomics, and Systems Biology, The University of Chicago, Chicago, IL, 60637, USA.
| | - Monika Scholz
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, 60637, USA
| | - Ilaria Merutka
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, 60637, USA
| | - David Biron
- Genetics, Genomics, and Systems Biology, The University of Chicago, Chicago, IL, 60637, USA.,Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, 60637, USA.,Department of Physics, The University of Chicago, Chicago, IL, 60637, USA
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29
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Zhuo W, Lu H, McGrath PT. Microfluidic platform with spatiotemporally controlled micro-environment for studying long-term C. elegans developmental arrests. LAB ON A CHIP 2017; 17:1826-1833. [PMID: 28466940 PMCID: PMC5521175 DOI: 10.1039/c6lc01573e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Animals' long-term survival is dependent on their ability to sense, filter and respond to their environment at multiple timescales. For example, during development, animals integrate environmental information, which can then modulate adult behavior and developmental trajectory. The neural and molecular mechanisms that underlie these changes are poorly understood. C. elegans is a powerful model organism to study such mechanisms; however, conventional plate-based culturing techniques are limited in their ability to consistently control and modulate an animal's environmental conditions. To address this need, we developed a microfluidics-based experimental platform capable of long-term culture of populations of developing C. elegans covering the L1 larval stage to adulthood, while achieving spatial consistency and temporal control of their environment. To prevent bacterial accumulation and maintain optimal flow characteristics and nutrient consistency over the operational period of over one hundred and fifty hours, several features of the microfluidic system and the peripheral equipment were optimized. By manipulating food and pheromone exposure over several days, we were able to demonstrate environmental-dependent changes to growth rate and entry to dauer, an alternative developmental state. We envision this system to be useful in studying the mechanisms underlying long timescale changes to behavior and development in response to environmental changes.
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Affiliation(s)
- Weipeng Zhuo
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0100
| | - Hang Lu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0100
- The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA
| | - Patrick T. McGrath
- The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332
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30
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Nekimken AL, Fehlauer H, Kim AA, Manosalvas-Kjono SN, Ladpli P, Memon F, Gopisetty D, Sanchez V, Goodman MB, Pruitt BL, Krieg M. Pneumatic stimulation of C. elegans mechanoreceptor neurons in a microfluidic trap. LAB ON A CHIP 2017; 17:1116-1127. [PMID: 28207921 PMCID: PMC5360562 DOI: 10.1039/c6lc01165a] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
New tools for applying force to animals, tissues, and cells are critically needed in order to advance the field of mechanobiology, as few existing tools enable simultaneous imaging of tissue and cell deformation as well as cellular activity in live animals. Here, we introduce a novel microfluidic device that enables high-resolution optical imaging of cellular deformations and activity while applying precise mechanical stimuli to the surface of the worm's cuticle with a pneumatic pressure reservoir. To evaluate device performance, we compared analytical and numerical simulations conducted during the design process to empirical measurements made with fabricated devices. Leveraging the well-characterized touch receptor neurons (TRNs) with an optogenetic calcium indicator as a model mechanoreceptor neuron, we established that individual neurons can be stimulated and that the device can effectively deliver steps as well as more complex stimulus patterns. This microfluidic device is therefore a valuable platform for investigating the mechanobiology of living animals and their mechanosensitive neurons.
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Affiliation(s)
- Adam L Nekimken
- Department of Mechanical Engineering, Stanford University, Stanford, California, USA. and Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA.
| | - Holger Fehlauer
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA.
| | - Anna A Kim
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA. and Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | | | - Purim Ladpli
- Department of Aeronautics and Astronautics, Stanford University, Stanford, California, USA
| | - Farah Memon
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Divya Gopisetty
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA.
| | - Veronica Sanchez
- Department of Mechanical Engineering, Stanford University, Stanford, California, USA.
| | - Miriam B Goodman
- Department of Mechanical Engineering, Stanford University, Stanford, California, USA. and Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA.
| | - Beth L Pruitt
- Department of Mechanical Engineering, Stanford University, Stanford, California, USA. and Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA. and Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Michael Krieg
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA.
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31
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Lee KS, Iwanir S, Kopito RB, Scholz M, Calarco JA, Biron D, Levine E. Serotonin-dependent kinetics of feeding bursts underlie a graded response to food availability in C. elegans. Nat Commun 2017; 8:14221. [PMID: 28145493 PMCID: PMC5296638 DOI: 10.1038/ncomms14221] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 12/08/2016] [Indexed: 11/16/2022] Open
Abstract
Animals integrate physiological and environmental signals to modulate their food uptake. The nematode C. elegans, whose food uptake consists of pumping bacteria from the environment into the gut, provides excellent opportunities for discovering principles of conserved regulatory mechanisms. Here we show that worms implement a graded feeding response to the concentration of environmental bacteria by modulating a commitment to bursts of fast pumping. Using long-term, high-resolution, longitudinal recordings of feeding dynamics under defined conditions, we find that the frequency and duration of pumping bursts increase and the duration of long pauses diminishes in environments richer in bacteria. The bioamine serotonin is required for food-dependent induction of bursts as well as for maintaining their high rate of pumping through two distinct mechanisms. We identify the differential roles of distinct families of serotonin receptors in this process and propose that regulation of bursts is a conserved mechanism of behaviour and motor control.
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Affiliation(s)
- Kyung Suk Lee
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Shachar Iwanir
- Department of Physics and the James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Ronen B. Kopito
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Monika Scholz
- Department of Physics and the James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - John A. Calarco
- FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - David Biron
- Department of Physics and the James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
- The Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Erel Levine
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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Herndon LA, Wolkow CA, Driscoll M, Hall DH. Effects of Ageing on the Basic Biology and Anatomy of C. elegans. HEALTHY AGEING AND LONGEVITY 2017. [DOI: 10.1007/978-3-319-44703-2_2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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33
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Lee KS, Lee LE, Levine E. HandKAchip - Hands-free killing assay on a chip. Sci Rep 2016; 6:35862. [PMID: 27775015 PMCID: PMC5075874 DOI: 10.1038/srep35862] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 10/05/2016] [Indexed: 01/24/2023] Open
Abstract
Small animals such as the roundworm C. elegans are excellent models for studying bacterial infection and host response, as well as for genetic and chemical screens. A key methodology is the killing assay, in which the number of surviving animals is tracked as a function of the time post infection. This is a labor-intensive procedure, prone to human error and subjective choices, and often involves undesired perturbation to the animals and their environment. In addition, the survival of animals is just one aspect of a multi-dimensional complex biological process. Here we report a microfluidic-based approach for performing killing assays in worms, compatible with standard assays performed on solid media. In addition to providing accurate and reproducible survival curves at a considerably reduced labor, this approach allows acquisition of a multitude of quantitative data with minimal undesired perturbations. These measurements are obtained automatically at a worm-by-worm resolution using a custom image processing workflow. The proposed approach is simple, scalable, and extendable, and is significantly more economical than standard manual protocols.
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Affiliation(s)
- Kyung Suk Lee
- Department of Physics and Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA
| | - Lucy E. Lee
- Department of Physics and Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA
| | - Erel Levine
- Department of Physics and Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA
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34
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Gritti N, Kienle S, Filina O, van Zon JS. Long-term time-lapse microscopy of C. elegans post-embryonic development. Nat Commun 2016; 7:12500. [PMID: 27558523 PMCID: PMC5512614 DOI: 10.1038/ncomms12500] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 07/08/2016] [Indexed: 11/09/2022] Open
Abstract
We present a microscopy technique that enables long-term time-lapse microscopy at single-cell resolution in moving and feeding Caenorhabditis elegans larvae. Time-lapse microscopy of C. elegans post-embryonic development is challenging, as larvae are highly motile. Moreover, immobilization generally leads to rapid developmental arrest. Instead, we confine larval movement to microchambers that contain bacteria as food, and use fast image acquisition and image analysis to follow the dynamics of cells inside individual larvae, as they move within each microchamber. This allows us to perform fluorescence microscopy of 10-20 animals in parallel with 20 min time resolution. We demonstrate the power of our approach by analysing the dynamics of cell division, cell migration and gene expression over the full ∼48 h of development from larva to adult. Our approach now makes it possible to study the behaviour of individual cells inside the body of a feeding and growing animal.
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Affiliation(s)
- Nicola Gritti
- FOM Institute AMOLF, Science Park 104, Amsterdam 1098 XG, The Netherlands
| | - Simone Kienle
- FOM Institute AMOLF, Science Park 104, Amsterdam 1098 XG, The Netherlands
| | - Olga Filina
- FOM Institute AMOLF, Science Park 104, Amsterdam 1098 XG, The Netherlands
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35
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Scholz M, Lynch DJ, Lee KS, Levine E, Biron D. A scalable method for automatically measuring pharyngeal pumping in C. elegans. J Neurosci Methods 2016; 274:172-178. [PMID: 27474347 DOI: 10.1016/j.jneumeth.2016.07.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/21/2016] [Accepted: 07/22/2016] [Indexed: 11/20/2022]
Abstract
BACKGROUND The nematode Caenorhabditis elegans is widely used for studying small neural circuits underlying behavior. In particular, the rhythmic feeding motions collectively termed pharyngeal pumping are regulated by a nearly autonomous network of 20 neurons of 14 types. Despite much progress achieved through laser ablation, genetics, electrophysiology, and optogenetics, key questions regarding the regulation of pumping remain open. NEW METHOD We describe the implementation and application of a scalable automated method for measuring pumping in controlled environments. Our implementation is affordable and flexible: key hardware and software elements can be modified to accommodate different requirements. RESULTS We demonstrate prolonged measurements under controlled conditions and the resulting high quality data. We show the scalability of our method, enabling high throughput, and its suitability for maintaining static and dynamic conditions. When food availability was oscillated, pumping rates were low as compared to steady conditions and pumping activity was not reliably modulated in response to changes in food concentration. COMPARISON WITH EXISTING METHOD The prevailing method for measuring rates of pumping relies on scoring by visual inspection of short recordings. Our automated method compares well with manual scoring. It enables detailed statistical characterization under experimental conditions not previously accessible and minimizes unintentional bias. CONCLUSIONS Our approach adds a powerful tool for studying pharyngeal pumping. It enhances the experimental versatility of assaying genetic and pharmacological manipulations and the ability to characterize the resulting behavior. Both the experimental setup and the analysis can be readily adapted to additional challenging motion detection problems.
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Affiliation(s)
- Monika Scholz
- James Franck Institute, The University of Chicago, Chicago, IL 60637, USA; Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
| | - Dylan J Lynch
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Kyung Suk Lee
- Department of Physics and Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA
| | - Erel Levine
- Department of Physics and Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA
| | - David Biron
- James Franck Institute, The University of Chicago, Chicago, IL 60637, USA; Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA; Department of Physics, The University of Chicago, Chicago, IL 60637, USA.
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36
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Gupta BP, Rezai P. Microfluidic Approaches for Manipulating, Imaging, and Screening C. elegans. MICROMACHINES 2016; 7:E123. [PMID: 30404296 PMCID: PMC6190076 DOI: 10.3390/mi7070123] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 06/23/2016] [Accepted: 07/11/2016] [Indexed: 11/17/2022]
Abstract
The nematode C. elegans (worm) is a small invertebrate animal widely used in studies related to fundamental biological processes, disease modelling, and drug discovery. Due to their small size and transparent body, these worms are highly suitable for experimental manipulations. In recent years several microfluidic devices and platforms have been developed to accelerate worm handling, phenotypic studies and screens. Here we review major tools and briefly discuss their usage in C. elegans research.
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Affiliation(s)
- Bhagwati P Gupta
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada.
| | - Pouya Rezai
- Department of Mechanical Engineering, York University, Toronto, ON M3J 1P3, Canada.
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37
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Huerre A, Jullien MC, Theodoly O, Valignat MP. Absolute 3D reconstruction of thin films topography in microfluidic channels by interference reflection microscopy. LAB ON A CHIP 2016; 16:911-916. [PMID: 26830018 DOI: 10.1039/c5lc01417d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The travel of droplets, bubbles, vesicles, capsules, living cells or small organisms in microchannels is a hallmark in microfluidics applications. A full description of the dynamics of such objects requires a quantitative understanding of the complex hydrodynamic and interfacial interactions between objects and channel walls. In this paper, we present an interferometric method that allows absolute topographic reconstruction of the interspace between an object and channel walls for objects confined in microfluidic channels. Wide field microscopic imaging in reflection interference contrast mode (RICM) is directly performed at the bottom wall of microfluidic chips. Importantly, we show that the reflections at both the lower and upper surface of the microchannel have to be considered in the quantitative analysis of the optical signal. More precisely, the contribution of the reflection at the upper surface is weighted depending on the light coherence length and channel height. Using several wavelengths and illumination apertures, our method allows reconstructing the topography of thin films on channel walls in a range of 0-500 nm, with a precision as accurate as 2 nm for the thinnest films. A complete description of the protocol is exemplified for oil in water droplets travelling in channels of height 10-400 μm at a speed up to 5 mm s(-1).
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Affiliation(s)
- A Huerre
- MMN, UMR CNRS Gulliver 7083, PSL research University, ESPCI ParisTech, 10 rue Vauquelin, F-75005 Paris, France
| | - M-C Jullien
- MMN, UMR CNRS Gulliver 7083, PSL research University, ESPCI ParisTech, 10 rue Vauquelin, F-75005 Paris, France
| | - O Theodoly
- LAI, INSERM UMR S 1067, CNRS UMR 7333, Aix-Marseille Universite 13009 Marseille, France
| | - M-P Valignat
- LAI, INSERM UMR S 1067, CNRS UMR 7333, Aix-Marseille Universite 13009 Marseille, France
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38
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A microfluidic device for efficient chemical testing using Caenorhabditis elegans. Biomed Microdevices 2015; 17:38. [DOI: 10.1007/s10544-015-9939-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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39
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Qiu Z, Tu L, Huang L, Zhu T, Nock V, Yu E, Liu X, Wang W. An integrated platform enabling optogenetic illumination of Caenorhabditis elegans neurons and muscular force measurement in microstructured environments. BIOMICROFLUIDICS 2015; 9:014123. [PMID: 25759756 PMCID: PMC4336256 DOI: 10.1063/1.4908595] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Accepted: 02/06/2015] [Indexed: 06/01/2023]
Abstract
Optogenetics has been recently applied to manipulate the neural circuits of Caenorhabditis elegans (C. elegans) to investigate its mechanosensation and locomotive behavior, which is a fundamental topic in model biology. In most neuron-related research, free C. elegans moves on an open area such as agar surface. However, this simple environment is different from the soil, in which C. elegans naturally dwells. To bridge up the gap, this paper presents integration of optogenetic illumination of C. elegans neural circuits and muscular force measurement in a structured microfluidic chip mimicking the C. elegans soil habitat. The microfluidic chip is essentially a ∼1 × 1 cm(2) elastomeric polydimethylsiloxane micro-pillar array, configured in either form of lattice (LC) or honeycomb (HC) to mimic the environment in which the worm dwells. The integrated system has four key modules for illumination pattern generation, pattern projection, automatic tracking of the worm, and force measurement. Specifically, two optical pathways co-exist in an inverted microscope, including built-in bright-field illumination for worm tracking and pattern generation, and added-in optogenetic illumination for pattern projection onto the worm body segment. The behavior of a freely moving worm in the chip under optogenetic manipulation can be recorded for off-line force measurements. Using wild-type N2 C. elegans, we demonstrated optical illumination of C. elegans neurons by projecting light onto its head/tail segment at 14 Hz refresh frequency. We also measured the force and observed three representative locomotion patterns of forward movement, reversal, and omega turn for LC and HC configurations. Being capable of stimulating or inhibiting worm neurons and simultaneously measuring the thrust force, this enabling platform would offer new insights into the correlation between neurons and locomotive behaviors of the nematode under a complex environment.
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Affiliation(s)
- Zhichang Qiu
- State Key Laboratory of Precision Measurement Technology and Instrument, Department of Precision Instruments, Tsinghua University , Beijing, China
| | - Long Tu
- State Key Laboratory of Precision Measurement Technology and Instrument, Department of Precision Instruments, Tsinghua University , Beijing, China
| | - Liang Huang
- State Key Laboratory of Precision Measurement Technology and Instrument, Department of Precision Instruments, Tsinghua University , Beijing, China
| | - Taoyuanmin Zhu
- State Key Laboratory of Precision Measurement Technology and Instrument, Department of Precision Instruments, Tsinghua University , Beijing, China
| | - Volker Nock
- Department of Electrical and Computer Engineering, University of Canterbury , Christchurch, New Zealand
| | - Enchao Yu
- School of Life Sciences, Tsinghua University , Beijing, China
| | - Xiao Liu
- School of Life Sciences, Tsinghua University , Beijing, China
| | - Wenhui Wang
- State Key Laboratory of Precision Measurement Technology and Instrument, Department of Precision Instruments, Tsinghua University , Beijing, China
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