scholarly journals Patterned substrates modulate growth and dynamics of 3D cellular systems

2019 ◽  
Author(s):  
Michael J. Fanous ◽  
Yanfen Li ◽  
Mikhail E. Kandel ◽  
Kristopher A. Kilian ◽  
Gabriel Popescu
Keyword(s):  
Cell Mass ◽  
Mouse Embryonic Fibroblast ◽  
Growth Patterns ◽  
Cellular Systems ◽  
Polar Coordinates ◽  
Interference Microscopy ◽  
Phase Imaging ◽  
Label Free ◽  
Patterned Substrates ◽  
Independent Manner

AbstractThe development of 3D cellular architectures during development and pathological processes involves intricate migratory patterns that are modulated by genetics and the surrounding microenvironment. The substrate composition of cell cultures has been demonstrated to influence growth, proliferation, and migration in 2D. Here we study the growth and dynamics of mouse embryonic fibroblast (MEF) cultures patterned in a tissue sheet which then exhibits 3D growth. Using gradient light interference microscopy (GLIM), a label-free quantitative phase imaging approach, we explored the influence of geometry on cell growth patterns and rotational dynamics. We apply, for the first time to our knowledge, dispersion-relation phase spectroscopy (DPS) in polar coordinates to generate the radial and rotational cell mass-transport. Our data show that cells cultured on engineered substrates undergo rotational transport in a radially independent manner and exhibit faster vertical growth than the control, unpatterned cells. The use of GLIM and polar DPS provides a novel quantitative approach to studying the effects of spatially patterned substrates on cell motility and growth.

scholarly journals Topography and refractometry of sperm cells using SLIM

2017 ◽  
Author(s):  
Lina Liu ◽  
Mikhail E. Kandel ◽  
Marcello Rubessa ◽  
Sierra Schreiber ◽  
Mathew Wheeler ◽  
...  
Keyword(s):  
Refractive Index ◽  
Interference Microscopy ◽  
Phase Imaging ◽  
Label Free ◽  
Quantitative Phase Imaging ◽  
Ensemble Averaging ◽  
Thickness Profile ◽  
Light Interference ◽  
Phase Sensitive

AbstractCharacterization of spermatozoon viability is a common test in treating infertility. Recently, it has been shown that label-free, phase-sensitive imaging can provide a valuable alternative for this type of assay. Here, we employ spatial light interference microscopy (SLIM) to decouple the thickness and refractive index information of individual cells. This procedure was enabled by quantitative phase imaging cells on media of two different refractive indices and using a numerical tool to remove the curvature from the cell tails. This way, we achieved ensemble averaging of topography and refractometry of 100 cells in each of the two groups. The results show that the thickness profile of the cell tail goes down to 150 nm and the refractive index can reach values of 1.6 close to the head.

scholarly journals Epi-illumination gradient light interference microscopy for imaging opaque structures

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Mikhail E. Kandel ◽  
Chenfei Hu ◽  
Ghazal Naseri Kouzehgarani ◽  
Eunjung Min ◽  
Kathryn Michele Sullivan ◽  
...  
Keyword(s):  
Multiple Scattering ◽  
Imaging Modality ◽  
Single Cells ◽  
Scattering Problem ◽  
Biological Tissues ◽  
Interference Microscopy ◽  
Model Organisms ◽  
Phase Imaging ◽  
Label Free ◽  
Light Interference

Abstract Multiple scattering and absorption limit the depth at which biological tissues can be imaged with light. In thick unlabeled specimens, multiple scattering randomizes the phase of the field and absorption attenuates light that travels long optical paths. These obstacles limit the performance of transmission imaging. To mitigate these challenges, we developed an epi-illumination gradient light interference microscope (epi-GLIM) as a label-free phase imaging modality applicable to bulk or opaque samples. Epi-GLIM enables studying turbid structures that are hundreds of microns thick and otherwise opaque to transmitted light. We demonstrate this approach with a variety of man-made and biological samples that are incompatible with imaging in a transmission geometry: semiconductors wafers, specimens on opaque and birefringent substrates, cells in microplates, and bulk tissues. We demonstrate that the epi-GLIM data can be used to solve the inverse scattering problem and reconstruct the tomography of single cells and model organisms.

scholarly journals Simultaneous cell traction and growth measurements using light

2017 ◽  
Author(s):  
Shamira Sridharan ◽  
Yanfen Li ◽  
Louis Foucard ◽  
Hassaan Majeed ◽  
Basanta Bhaduri ◽  
...  
Keyword(s):  
Cell Growth ◽  
Displacement Field ◽  
Cancer Metastasis ◽  
Cell Function ◽  
Imaging Modality ◽  
Cell Mass ◽  
Interference Microscopy ◽  
Periodic Signal ◽  
Label Free ◽  
Spatial And Temporal Scales

ABSTRACTUnderstanding cell mechanotransduction is important for discerning matrix structure-cell function relationships underlying health and disease. Despite the crucial role of mechanochemical signaling in phenomena such as cell migration, proliferation, and differentiation, measuring the cell-generated forces at the interface with the extracellular matrix during these biological processes remains challenging. An ideal method would provide continuous, non-destructive images of the force field applied by cells, over broad spatial and temporal scales, while simultaneously revealing the cell biological process under investigation. Toward this goal, we present the integration of a new real-time traction stress imaging modality, Hilbert phase dynamometry (HPD), with the technique of spatial light interference microscopy (SLIM) for label free monitoring of cell growth. HPD relies on extracting the displacement field in a deformable substrate, which is chemically patterned with a fluorescent grid. The displacements introduced by the cell are captured by the phase of the periodic signal associated with the grid, borrowing concepts from holography. The displacement field is uniquely converted into forces by solving an elasticity inverse problem. Because the measurement of displacement only uses the epi-fluorescence channel of an inverted microscope, we can simultaneously achieve measurements in transmission. We performed SLIM and extracted cell mass on the same field of view in addition to the measured displacement field. We used this technique to study mesenchymal stem cells and found that cells undergoing osteogenesis and adipogenesis exerted larger and more dynamic stresses than their precursor. Our results indicate that the MSCs develop the smallest forces and growth rates. We anticipate that simultaneous cell growth and traction measurements will improve our understanding of mechanotransduction, particularly during dynamic processes where the matrix properties provide context to guide cells towards a physiological or pathological outcome, e.g., tissue morphogenesis, or cancer metastasis.

scholarly journals Cancer Cells Viscoelasticity Measurement by Quantitative Phase and Flow Stress Induction

2021 ◽  
Author(s):  
Tomas Vicar ◽  
Jaromir Gumulec ◽  
Jiri Chmelik ◽  
Jiri Navratil ◽  
Radim Kolar ◽  
...  
Keyword(s):  
Shear Modulus ◽  
Cell Mass ◽  
Time Lapse ◽  
Cytochalasin D ◽  
Phase Imaging ◽  
Label Free ◽  
Height Measurement ◽  
Stress Induction ◽  
Cell Parameters ◽  
Quantitative Phase

Cell viscoelastic properties are affected by the cell cycle, differentiation, pathological processes such as malignant transformation. Therefore, evaluation of the mechanical properties of the cells proved to be an approach to obtaining information on the functional state of the cells. Most of the currently used methods for cell mechanophenotypisation are limited by low robustness or the need for highly expert operation. In this paper, the system and method for viscoelasticity measurement using shear stress induction by fluid flow is described and tested. Quantitative Phase Imaging (QPI) is used for image acquisition because this technique enables to quantify optical path length delays introduced by the sample, thus providing a label-free objective measure of morphology and dynamics. Viscosity and elasticity determination were refined using a new approach based on the linear system model and parametric deconvolution. The proposed method allows high-throughput measurements during live cell experiments and even through a time-lapse, where we demonstrated the possibility of simultaneous extraction of shear modulus, viscosity, cell morphology, and QPI-derived cell parameters like circularity or cell mass. Additionally, the proposed method provides a simple approach to measure cell refractive index with the same setup, which is required for reliable cell height measurement with QPI, an essential parameter for viscoelasticity calculation. Reliability of the proposed viscoelasticity measurement system was tested in several experiments including cell types of different Young/shear modulus and treatment with cytochalasin D or docetaxel, and an agreement with atomic force microscopy was observed. The applicability of the proposed approach was also confirmed by a time-lapse experiment with cytochalasin D washout, where an increase of stiffness corresponded to actin repolymerisation in time.

Label-free, mass-sensitive single-molecule imaging using interferometric scattering microscopy

2020 ◽  
Author(s):  
Nikolas Hundt
Keyword(s):  
Single Molecule ◽  
Cellular Systems ◽  
Single Molecule Imaging ◽  
Label Free ◽  
Measurement Sensitivity ◽  
Mass Distributions ◽  
Quantitative Measurements ◽  
Contrast Mechanism ◽  
Cellular Components ◽  
Scattering Signal

Abstract Single-molecule imaging has mostly been restricted to the use of fluorescence labelling as a contrast mechanism due to its superior ability to visualise molecules of interest on top of an overwhelming background of other molecules. Recently, interferometric scattering (iSCAT) microscopy has demonstrated the detection and imaging of single biomolecules based on light scattering without the need for fluorescent labels. Significant improvements in measurement sensitivity combined with a dependence of scattering signal on object size have led to the development of mass photometry, a technique that measures the mass of individual molecules and thereby determines mass distributions of biomolecule samples in solution. The experimental simplicity of mass photometry makes it a powerful tool to analyse biomolecular equilibria quantitatively with low sample consumption within minutes. When used for label-free imaging of reconstituted or cellular systems, the strict size-dependence of the iSCAT signal enables quantitative measurements of processes at size scales reaching from single-molecule observations during complex assembly up to mesoscopic dynamics of cellular components and extracellular protrusions. In this review, I would like to introduce the principles of this emerging imaging technology and discuss examples that show how mass-sensitive iSCAT can be used as a strong complement to other routine techniques in biochemistry.

scholarly journals Monitoring Reactivation of Latent HIV by Label-Free Gradient Light Interference Microscopy

iScience ◽  
2021 ◽  
pp. 102940
Author(s):  
Neha Goswami ◽  
Yiyang Lu ◽  
Mikhail E. Kandel ◽  
Michael J. Fanous ◽  
Kathrin Bohn-Wippert ◽  
...  
Keyword(s):  
Interference Microscopy ◽  
Label Free ◽  
Light Interference ◽  
Latent Hiv

Label-free second-harmonic phase imaging of biological specimen by digital holographic microscopy

2010 ◽  
Vol 35 (24) ◽  
pp. 4102 ◽  
Author(s):  
Etienne Shaffer ◽  
Corinne Moratal ◽  
Pierre Magistretti ◽  
Pierre Marquet ◽  
Christian Depeursinge
Keyword(s):  
Second Harmonic ◽  
Digital Holographic Microscopy ◽  
Phase Imaging ◽  
Label Free ◽  
Biological Specimen ◽  
Harmonic Phase ◽  
Holographic Microscopy ◽  
Harmonic Phase Imaging
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