Automated and controlled mechanical stimulation and functional imaging in vivo in C. elegans

Cho, Yong-Min; Porto, Daniel; Hwang, Hyundoo; Grundy, Laura J; Schafer, William R.; Lu, Hang

doi:10.1039/c7lc00465f

Cited by 60 publications

(93 citation statements)

References 60 publications

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“…To study touch sensitivity of C. elegans larvae, Cho et al (2018) presented a device adapted from previous devices for studying adult worms (Cho et al, 2017; Nekimken, Fehlauer, et al, 2017), with a fluorescent calcium sensor, GCaMP (Chen et al, 2013), as a readout for neuron activation. To mechanically stimulate a worm, the authors used actuators similar to those described in Section 3, but required a different polymer formulation, resulting in a lower modulus of elasticity to enable actuation suitable for small larvae.…”

Section: Microfluidics For Mechanobiology Of Model Organismsmentioning

confidence: 99%

“…Nekimken, Fehlauer, et al (2017) and Cho et al (2017) used similar lateral pneumatic actuators for stimulation and a fluorescent calcium sensor, GCaMP (Chen et al, 2013), for readout of neuronal activity. With our device, which is described in Section 4, we found that the touch receptor neurons were also activated with a blue light stimulus, such as the excitation light for green fluorescent proteins.…”

Section: Microfluidics For Mechanobiology Of Model Organismsmentioning

confidence: 99%

“…The device presented by Cho et al (2017) used an active trapping strategy consisting of two pairs of laterally deformable actuators that hold a worm in place while a third pair between the two sets of trapping actuators applies mechanical stimuli to the worm. Using step function stimuli, they demonstrated that increases in stimulus magnitude or duration can increase the activation of touch receptor neurons.…”

Section: Microfluidics For Mechanobiology Of Model Organismsmentioning

confidence: 99%

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Microfluidics for mechanobiology of model organisms

Kim

Nekimken

Fechner

et al. 2018

Methods in Cell Biology

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Mechanical stimuli play a critical role in organ development, tissue homeostasis, and disease. Understanding how mechanical signals are processed in multicellular model systems is critical for connecting cellular processes to tissue- and organism-level responses. However, progress in the field that studies these phenomena, mechanobiology, has been limited by lack of appropriate experimental techniques for applying repeatable mechanical stimuli to intact organs and model organisms. Microfluidic platforms, a subgroup of microsystems that use liquid flow for manipulation of objects, are a promising tool for studying mechanobiology of small model organisms due to their size scale and ease of customization. In this work, we describe design considerations involved in developing a microfluidic device for studying mechanobiology. Then, focusing on worms, fruit flies, and zebrafish, we review current microfluidic platforms for mechanobiology of multicellular model organisms and their tissues and highlight research opportunities in this developing field.

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Section: Microfluidics For Mechanobiology Of Model Organismsmentioning

confidence: 99%

Section: Microfluidics For Mechanobiology Of Model Organismsmentioning

confidence: 99%

Section: Microfluidics For Mechanobiology Of Model Organismsmentioning

confidence: 99%

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Microfluidics for mechanobiology of model organisms

Kim

Nekimken

Fechner

et al. 2018

Methods in Cell Biology

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“…This method has been used to explore the biomechanical properties of the worm’s body 18 and their effects on touch sensitivity 19 , and to develop a biophysical model of mechanotransduction in the touch cells 20 . Another approach is to immobilize a single worm with glue 9 or a microfluidic trap 21,22 and use a glass probe or pneumatic indenter to apply direct stimulus while monitoring calcium transients or electrophysiological activity 23 . However, no method to date has combined the application of a localized, tunable, mechanical stimulus with behavioral recording of the responses of many worms at the same time.…”

Section: Introductionmentioning

confidence: 99%

ComparingCaenorhabditis elegansgentle and harsh touch response behavior using a multiplexed hydraulic microfluidic device

McClanahan

Fang-Yen

2017

Integrative Biology

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The roundworm Caenorhabditis elegans is an important model system for understanding the genetics and physiology of touch. Classical assays for C. elegans touch, which involve manually touching the animal with a probe and observing its response, are limited by their low throughput and qualitative nature. We developed a microfluidic device in which several dozen animals are subject to spatially localized mechanical stimuli with variable amplitude. The device contains 64 sinusoidal channels through which worms crawl, and hydraulic valves that deliver touch stimuli to the worms. We used this assay to characterize the behavioral responses to gentle touch stimuli and the less well studied harsh (nociceptive) touch stimuli. First, we measured the relative response thresholds of gentle and harsh touch. Next, we quantified differences in the receptive fields between wild type worms and a mutant with non-functioning posterior touch receptor neurons. We showed that under gentle touch the receptive field of the anterior touch receptor neurons extends into the posterior half of the body. Finally, we found that the behavioral response to gentle touch does not depend on the locomotion of the animal immediately prior to the stimulus, but does depend on the location of the previous touch. Responses to harsh touch, on the other hand, did not depend on either previous velocity or stimulus location. Differences in gentle and harsh touch response characteristics may reflect the different innervation of the respective mechanosensory cells. Our assay will facilitate studies of mechanosensation, sensory adaptation, and nociception.

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“…From optogenetic dissection studies, TRN activation is known to be sufficient to activate such behaviors: stimulation of the three anterior neurons (ALML, ALMR, and AVM) causes forward-moving animals to reverse direction, while stimulation of two posterior neurons (PLML and PLMR) results in a speed-up 8 . A third posterior neuron, PVM, is activated via mechanical stimulation [9][10][11] but is not required for behavioral responses to gentle touch 6,7 . Thus, five of the six TRNs are necessary and sufficient to produce touch-evoked avoidance behaviors in adult hermaphrodites.…”

Section: Introductionmentioning

confidence: 99%

The Tactile Receptive Fields of Freely Moving Caenorhabditis elegans Nematodes

Mazzochette¹,

Nekimken

Loizeau

et al. 2018

Preprint

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Sensory neurons embedded in skin are responsible for the sense of touch. In humans and other mammals, touch sensation depends on thousands of diverse somatosensory neurons. By contrast, Caenorhabditis elegans nematodes have six gentle touch receptor neurons linked to simple behaviors. The classical touch assay uses an eyebrow hair to stimulate freely moving C. elegans, evoking evasive behavioral responses.While this assay has led to the discovery of genes required for touch sensation, it does not provide control over stimulus strength or position. Here, we present an integrated system for performing automated, quantitative touch assays that circumvents these limitations and incorporates automated measurements of behavioral responses. Highly Automated Worm Kicker (HAWK) unites microfabricated silicon force sensors and video analysis with real-time force and position control. Using this system, we stimulated animals along the anterior-posterior axis and compared responses in wild-type and spc-1(dn) transgenic animals, which have a touch defect due to expression of a dominant-negative a spectrin protein fragment.As expected from prior studies, delivering large stimuli anterior to the mid-point of the body evoked a reversal, but such a stimulus applied posterior to the mid-point evoked a speed-up. The probability of evoking a response of either kind depended on stimulus strength and location; once initiated, the magnitude and quality of both reversal and speed-up behavioral responses were uncorrelated with stimulus location, strength, or the absence or presence of the spc-1(dn) transgene. Wild-type animals failed to respond when the stimulus was applied near the mid-point. These results establish that stimulus strength and location govern the activation of a stereotyped motor program and that the C. elegans body surface consists of two receptive fields separated by a gap.

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Automated and controlled mechanical stimulation and functional imaging in vivo in C. elegans

Abstract: A new automated microfluidic platform can deliver a wide range of mechanical stimuli for functional neural imaging in C. elegans.

Cited by 60 publications

References 60 publications

Microfluidics for mechanobiology of model organisms

Microfluidics for mechanobiology of model organisms

ComparingCaenorhabditis elegansgentle and harsh touch response behavior using a multiplexed hydraulic microfluidic device

The Tactile Receptive Fields of Freely Moving Caenorhabditis elegans Nematodes

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