Live Cell Imaging during Mechanical Stretch

Rapalo, Gabriel; Herwig, Josh D.; Hewitt, Robert; Wilhelm, K.; Waters, Christopher M.; Roan, Esra

doi:10.3791/52737

Cited by 8 publications

(11 citation statements)

References 27 publications

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“…In order to follow such an approach, we and others have bioengineered isotropic stretch systems based on either radial displacement of point-fixations on the outer periphery of a circular stretch-chamber (Rapalo et al, 2015; Schürmann et al, 2016) or an iris-like mechanism (Majd et al, 2009). Those will be the focus of the following sections, followed by new application data from our IsoStretcher system to ventricular cardiomyocytes.…”

Section: Indenter Ring-based Inplane Cell Stretch Systems With Flexibmentioning

confidence: 99%

“…An improved current version (2018) is shown. (B) Radial displacement PDMS chamber lip clamp system introduced by Rapalo et al (2015) to combine isotropic stretch of cells in large culture dishes (about 4 cm diameter) for confocal of atomic force microscopy. Maximum linear strain was 20%.…”

Section: Introductionmentioning

confidence: 99%

“…Maximum linear strain was 20%. Taken with permission from Rapalo et al (2015). (C) An iris-like actuated system that uses eight PDMS substrate (HERS: high-extension silicon rubber) holding arms that are screwed to an outer frame allowing rotational degree of freedom of movement while the inner substrate pillar will be pulled toward the outer frame once the outer ring is actuated.…”

Section: Introductionmentioning

confidence: 99%

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Stretch in Focus: 2D Inplane Cell Stretch Systems for Studies of Cardiac Mechano-Signaling

Friedrich

Merten

Schneidereit

et al. 2019

Front. Bioeng. Biotechnol.

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Mechanobiology is a rapidly growing interdisciplinary research field, involving biophysics, molecular and cell biology, biomedical engineering, and medicine. Rapid progress has been possible due to emerging devices and tools engineered for studies of the effect of mechanical forces, such as stretch or shear force, impacting on biological cells and tissues. In response to such mechanical stimuli, cells possess various mechanosensors among which mechanosensitive ion channels are molecular transducers designed to convert mechanical stimuli into electrical and/or biochemical intracellular signals on millisecond time scales. To study their role in cellular signaling pathways, devices have been engineered that enable application of different strain protocols to cells allowing for determination of the stress-strain relationship or other, preferably optical, readouts. Frequently, these devices are mounted on fluorescence microscopes, allowing simultaneous investigation of cellular mechanotransduction processes combined with live-cell imaging. Mechanical stress in organs/tissues can be complex and multiaxial, e.g., in hollow organs, like lung alveoli, bladder, or the heart. Therefore, biomedical engineers have, in recent years, developed devices based on elastomeric membranes for application of biaxial or multiaxial stretch to 2D substrate-adhered or even 3D-embedded cells. Here, we review application of stretch technologies to cellular mechanotransduction with a focus on cardiovascular systems. We also present new results obtained by our IsoStretcher device to examine mechanosensitivity of adult ventricular cardiomyocytes. We show that sudden isotropic stretch of cardiomyocytes can already trigger arrhythmic Ca 2+ transients on the single cell level.

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Section: Indenter Ring-based Inplane Cell Stretch Systems With Flexibmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Stretch in Focus: 2D Inplane Cell Stretch Systems for Studies of Cardiac Mechano-Signaling

Friedrich

Merten

Schneidereit

et al. 2019

Front. Bioeng. Biotechnol.

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“…This type of membrane allows stretching of the confluent layer of cells and is used as a model for motion-induced stress in epithelial lung tissue. 36 Mitochondria were labeled with MitoTracker ® Green. Immediately before imaging, the membrane was transferred to a slide and capped with a coverglass (No.…”

Section: Data Acquisitionmentioning

confidence: 99%

Performance evaluation of extended depth of field microscopy in the presence of spherical aberration and noise

2018

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Effectiveness of extended depth of field microscopy (EDFM) implementation with wavefront encoding methods is reduced by depth-induced spherical aberration (SA) due to reliance of this approach on a defined point spread function (PSF). Evaluation of the engineered PSF's robustness to SA, when a specific phase mask design is used, is presented in terms of the final restored image quality. Synthetic intermediate images were generated using selected generalized cubic and cubic phase mask designs. Experimental intermediate images were acquired using the same phase mask designs projected from a liquid crystal spatial light modulator. Intermediate images were restored using the penalized space-invariant expectation maximization and the regularized linear least squares algorithms. In the presence of depth-induced SA, systems characterized by radially symmetric PSFs, coupled with model-based computational methods, achieve microscope imaging performance with fewer deviations in structural fidelity (e.g., artifacts) in simulation and experiment and 50% more accurate positioning of 1-μm beads at 10-μm depth in simulation than those with radially asymmetric PSFs. Despite a drop in the signal-to-noise ratio after processing, EDFM is shown to achieve the conventional resolution limit when a model-based reconstruction algorithm with appropriate regularization is used. These trends are also found in images of fixed fluorescently labeled brine shrimp, not adjacent to the coverslip, and fluorescently labeled mitochondria in live cells.

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“…reversible shape-memory actuator | mesenchymal stem cells | calcium influx | HDAC1 | RUNX2 I n bioinformatics, the mass collection and mass distribution of biological information has enabled the unparalleled collaborative examination of complex cellular systems, detecting previously hidden patterns in the behavior of a variety of organisms. Current cell-signaling methods, however, rely on bulky controlling devices that regulate the transmission of decoupled thermomechanical information, limiting our control of the cellular microenvironment, but because of their expense, also the standardization of protocols that comes with widespread adoption by the scientific community (1,2). Programmable materials are needed that enable the encoding of information into cell culture substrates, allowing multiple physical signals or inputs to be communicated to cells controllably and autonomously.…”

mentioning

confidence: 99%

Polymeric sheet actuators with programmable bioinstructivity

Deng

Wang

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Stem cells are capable of sensing and processing environmental inputs, converting this information to output a specific cell lineage through signaling cascades. Despite the combinatorial nature of mechanical, thermal, and biochemical signals, these stimuli have typically been decoupled and applied independently, requiring continuous regulation by controlling units. We employ a programmable polymer actuator sheet to autonomously synchronize thermal and mechanical signals applied to mesenchymal stem cells (MSCs). Using a grid on its underside, the shape change of polymer sheet, as well as cell morphology, calcium (Ca2+) influx, and focal adhesion assembly, could be visualized and quantified. This paper gives compelling evidence that the temperature sensing and mechanosensing of MSCs are interconnected via intracellular Ca2+. Up-regulated Ca2+ levels lead to a remarkable alteration of histone H3K9 acetylation and activation of osteogenic related genes. The interplay of physical, thermal, and biochemical signaling was utilized to accelerate the cell differentiation toward osteogenic lineage. The approach of programmable bioinstructivity provides a fundamental principle for functional biomaterials exhibiting multifaceted stimuli on differentiation programs. Technological impact is expected in the tissue engineering of periosteum for treating bone defects.

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Live Cell Imaging during Mechanical Stretch

Cited by 8 publications

References 27 publications

Stretch in Focus: 2D Inplane Cell Stretch Systems for Studies of Cardiac Mechano-Signaling

Stretch in Focus: 2D Inplane Cell Stretch Systems for Studies of Cardiac Mechano-Signaling

Performance evaluation of extended depth of field microscopy in the presence of spherical aberration and noise

Polymeric sheet actuators with programmable bioinstructivity

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