Long-term Brillouin imaging of live cells with reduced absorption-mediated damage at 660nm wavelength

Nikolić, Miloš; Scarcelli, Giuliano

doi:10.1364/boe.10.001567

Cited by 56 publications

(50 citation statements)

References 39 publications

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“…Although a relatively high power was used for Brillouin imaging, confocal imaging analysis showed no difference in Brillouin imaged and unimaged retinas, and previous research has shown no damage to cells until a much higher incident power. 40 One major limitation of this work is that Brillouin microscopy can only provide measurements of the tissue bulk modulus instead of the quantitative measurement of elasticity. We have previously demonstrated quantitative measurements of crystalline lens elasticity by combining Brillouin microscopy with OCE.…”

Section: Discussionmentioning

confidence: 99%

Characterization of retinal biomechanical properties using Brillouin microscopy

et al. 2020

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Significance: The retina is critical for vision, and several diseases may alter its biomechanical properties. However, assessing the biomechanical properties of the retina nondestructively is a challenge due to its fragile nature and location within the eye globe. Advancements in Brillouin spectroscopy have provided the means for nondestructive investigations of retina biomechanical properties. Aim: We assessed the biomechanical properties of mouse retinas using Brillouin microscopy noninvasively and showed the potential of Brillouin microscopy to differentiate the type and layers of retinas based on stiffness. Approach: We used Brillouin microscopy to quantify stiffness of fresh and paraformaldehyde (PFA)-fixed retinas. As further proof-of-concept, we demonstrated a change in the stiffness of a retina with N-methyl-D-aspartate (NMDA)-induced damage, compared to an undamaged sample. Results: We found that the retina layers with higher cell body density had higher Brillouin modulus compared to less cell-dense layers. We have also demonstrated that PFA-fixed retina samples were stiffer compared with fresh samples. Further, NMDA-induced neurotoxicity leads to retinal ganglion cell (RGC) death and reactive gliosis, increasing the stiffness of the RGC layer. Conclusion: Brillouin microscopy can be used to characterize the stiffness distribution of the layers of the retina and can be used to differentiate tissue at different conditions based on biomechanical properties.

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Section: Discussionmentioning

confidence: 99%

Characterization of retinal biomechanical properties using Brillouin microscopy

et al. 2020

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“…Attached cells were imaged by point‐scanning them through the laser spot with a motorized stage. In these 2D imaging experiments, instead of using 532‐nm laser source, a 660‐nm laser with ≈20 mW was used to remove phototoxic [ 63 ] and used an objective lens with NA of 0.7 (Olympus LUCPLFLN60X) to achieve appropriate spatial resolution of 0.58 µm × 0.58 µm × 2.8 µm. The measured Brillouin shift at 660 nm was scaled to 532 nm based on the wavelength relationship.…”

Section: Methodsmentioning

confidence: 99%

“…Cell viability was checked by monitoring the absence of blebs during and after each experiment. [ 63 ]…”

Section: Methodsmentioning

confidence: 99%

Nuclear Mechanics within Intact Cells Is Regulated by Cytoskeletal Network and Internal Nanostructures

Zhang

Alisafaei

Nikolić

et al. 2020

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The mechanical properties of the cellular nucleus are extensively studied as they play a critical role in important processes, such as cell migration, gene transcription, and stem cell differentiation. While the mechanical properties of the isolated nucleus have been tested, there is a lack of measurements about the mechanical behavior of the nucleus within intact cells and specifically about the interplay of internal nuclear components with the intracellular microenvironment, because current testing methods are based on contact and only allow studying the nucleus after isolation from a cell or disruption of cytoskeleton. Here, all‐optical Brillouin microscopy and 3D chemomechanical modeling are used to investigate the regulation of nuclear mechanics in physiological conditions. It is observed that the nuclear modulus can be modulated by epigenetic regulation targeting internal nuclear nanostructures such as lamin A/C and chromatin. It is also found that nuclear modulus is strongly regulated by cytoskeletal behavior through a robust mechanism conserved in different culturing conditions. Given the active role of cytoskeletal modulation in nearly all cell functions, this work will enable to reveal highly relevant mechanisms of nuclear mechanical regulations in physiological and pathological conditions.

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“…Cells were imaged with an integrated fluorescent and confocal Brillouin microscope based on a commercial microscope stand (IX81; Olympus) (45). A ~15-mW continuous-wave laser (Torus, Laser Quantum; 660 nm) light was used to excite the Brillouin signal.…”

Section: Confocal Brillouin Microscopymentioning

confidence: 99%

Dorsoventral polarity directs cell responses to migration track geometries

et al. 2020

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How migrating cells differentially adapt and respond to extracellular track geometries remains unknown. Using intravital imaging, we demonstrate that invading cells exhibit dorsoventral (top-to-bottom) polarity in vivo. To investigate the impact of dorsoventral polarity on cell locomotion through different confining geometries, we fabricated microchannels of fixed cross-sectional area, albeit with distinct aspect ratios. Vertical confinement, exerted along the dorsoventral polarity axis, induces myosin II–dependent nuclear stiffening, which results in RhoA hyperactivation at the cell poles and slow bleb-based migration. In lateral confinement, directed perpendicularly to the dorsoventral polarity axis, the absence of perinuclear myosin II fails to increase nuclear stiffness. Hence, cells maintain basal RhoA activity and display faster mesenchymal migration. In summary, by integrating microfabrication, imaging techniques, and intravital microscopy, we demonstrate that dorsoventral polarity, observed in vivo and in vitro, directs cell responses in confinement by spatially tuning RhoA activity, which controls bleb-based versus mesenchymal migration.

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Long-term Brillouin imaging of live cells with reduced absorption-mediated damage at 660nm wavelength

Cited by 56 publications

References 39 publications

Characterization of retinal biomechanical properties using Brillouin microscopy

Characterization of retinal biomechanical properties using Brillouin microscopy

Nuclear Mechanics within Intact Cells Is Regulated by Cytoskeletal Network and Internal Nanostructures

Dorsoventral polarity directs cell responses to migration track geometries

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