Assessment of Mechanical Properties of Adherent Living Cells by Bead Micromanipulation: Comparison of Magnetic Twisting Cytometry vs Optical Tweezers

2002 ◽  
Vol 124 (4) ◽  
pp. 408-421 ◽  
Author(s):  
Vale´rie M. Laurent ◽  
Sylvie He´non ◽  
Emmanuelle Planus ◽  
Redouane Fodil ◽  
Martial Balland ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Optical Tweezers ◽  
Viscoelastic Properties ◽  
Young Modulus ◽  
Living Cells ◽  
Alveolar Epithelial Cells ◽  
Time Constants ◽  
Alveolar Epithelial ◽  
Magnetic Twisting Cytometry ◽  
Relaxation Time Constants

We compare the measurements of viscoelastic properties of adherent alveolar epithelial cells by two micromanipulation techniques: (i) magnetic twisting cytometry and (ii) optical tweezers, using microbeads of same size and similarly attached to F-actin. The values of equivalent Young modulus E, derived from linear viscoelasticity theory, become consistent when the degree of bead immersion in the cell is taken into account. E-values are smaller in (i) than in (ii): ∼34–58 Pa vs ∼29–258 Pa, probably because higher stress in (i) reinforces nonlinearity and cellular plasticity. Otherwise, similar relaxation time constants, around 2 s, suggest similar dissipative mechanisms.

Real-Time Investigation of Engineered Nanomaterials Cytotoxicity in Living Alveolar Epithelia with Hopping Probe Ion Conductance Microscopy

2013 ◽  
Vol 651 ◽  
pp. 24-28 ◽  
Author(s):  
Xiao Liu ◽  
Hui Zhu ◽  
Hu Jie Lu ◽  
Ying Li ◽  
Jian Ning Zhang ◽  
...  
Keyword(s):  
Real Time ◽  
Imaging Techniques ◽  
Living Cells ◽  
Alveolar Epithelial Cells ◽  
Engineered Nanomaterials ◽  
Ion Conductance ◽  
Physiological Conditions ◽  
Alveolar Epithelial ◽  
Ideal Tool ◽  
Topographic Imaging

Widely used engineered nanomaterials (NMs) display unique properties that may have impact on human health, and thus require a reliable evaluation of their potential cytotoxicity. There is a continuing need for real-time imaging techniques capable of studying the interactions between NMs and living alveolar epithelial cells under physiological conditions. A new developed noninvasive HPICM is designed for continuous high-resolution topographic imaging of living cells, which makes it an ideal tool to study NMs cytotoxicity in living alveolar epithelia by performing reliable repetitive scanning. In this review, we concisely introduced the operation principle of HPICM and its applications to real-time investigation of engineered NMs cytotoxicity in living alveolar epithelia. Published results demonstrate that non-contact HPICM combined with patch-clamp has the potential to become a powerful microscopy for real-time studies of NM-cell interactions under physiological conditions.

Mechanical properties of alveolar epithelial cells in culture

2001 ◽  
Vol 91 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Jorge C. Berrios ◽  
Mark A. Schroeder ◽  
Rolf D. Hubmayr
Keyword(s):  
Mechanical Properties ◽  
Shape Change ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Alveolar Epithelial Cells ◽  
Alveolar Epithelial ◽  
Membrane Cytoskeleton ◽  
Apparent Stiffness ◽  
Force Transfer ◽  
Definition Of

With the use of magnetic twisting cytometry, we characterized the mechanical properties of rat type II alveolar epithelial (ATII) cells in primary culture and examined whether the cells' state of differentiation and the application of deforming stresses influence their resistance to shape change. Cells were harvested from rat lungs as previously described (Dobbs LG. Am J Physiol Lung Cell Mol Physiol 258: L134–L147, 1990) and plated at a density of 1 × 106 cells/cm2 in fibronectin-coated 96 Remova wells, and their mechanical properties were measured 2–9 days later. We show 1) that ATII cells form much stronger bonds with RGD-coated beads than they do with albumin- or acetylated low-density lipoprotein-coated beads, 2) that RGD-mediated bonds seemingly “mature” during the first 60 min of bead contact, 3) that the apparent stiffness of ATII cells increases with days in culture, 4) that stiffness falls when the RGD-coated beads are intermittently oscillated at 0.3 Hz, and 5) that this fall cannot be attributed to exocytosis-related remodeling of the subcortical cytoskeleton. Although the mechanisms of force transfer between basement membrane, cytoskeleton, and plasma membrane of ATII cells remain to be resolved, such analyses undoubtedly require definition of the cell's mechanical properties. To our knowledge, the results presented here provide the first data on this topic.

NANOTECHNOLOGY AND HUMAN DISEASES

COSMOS ◽  
2007 ◽  
Vol 03 (01) ◽  
pp. 89-101 ◽  
Author(s):  
GABRIEL YEW HOE LEE ◽  
CHWEE TECK LIM
Keyword(s):  
Mechanical Properties ◽  
Molecular Biology ◽  
Disease Progression ◽  
Viscoelastic Properties ◽  
State Of The Art ◽  
Living Cells ◽  
Molecular Structures ◽  
Human Diseases ◽  
Diagnosis And Treatment ◽  
Basic Principles

Tissues, cells and biomolecules can experience changes in their structural and mechanical properties during the occurrence of certain diseases. Recent advances in the fields of nanotechnology, biomechanics and cell and molecular biology have led to the development of state-of-the-art and novel biophysical and nanotechnological tools to probe the mechanical properties of individual living cells and biomolecules. Here we will review the basic principles and application of some of these nanotechnological tools used to relate changes in the elastic and viscoelastic properties of cells to alterations in the cellular and molecular structures induced by diseases such as malaria and cancer. Knowing the ways and the extent to which mechanical properties of living cells are altered with the onset of disease progression will be crucial for us to gain vital insights into the pathogenesis and pathophysiology of malaria and cancer, and potentially offers the opportunity to develop new and better methods of detection, diagnosis and treatment.

scholarly journals Shear Stress Induced Reorganization of the Keratin Intermediate Filament Network Requires Phosphorylation by Protein Kinase C ζ

2009 ◽  
Vol 20 (11) ◽  
pp. 2755-2765 ◽  
Author(s):  
Sivaraj Sivaramakrishnan ◽  
Jaime L. Schneider ◽  
Albert Sitikov ◽  
Robert D. Goldman ◽  
Karen M. Ridge
Keyword(s):  
Mechanical Properties ◽  
Shear Stress ◽  
Epithelial Cells ◽  
Polymer Network ◽  
A549 Cells ◽  
Alveolar Epithelial Cells ◽  
Dependent Manner ◽  
Structural Remodeling ◽  
Alveolar Epithelial ◽  
Pkc Ζ

Keratin intermediate filaments (KIFs) form a fibrous polymer network that helps epithelial cells withstand external mechanical forces. Recently, we established a correlation between the structure of the KIF network and its local mechanical properties in alveolar epithelial cells. Shear stress applied across the cell surface resulted in the structural remodeling of KIF and a substantial increase in the elastic modulus of the network. This study examines the mechanosignaling that regulates the structural remodeling of the KIF network. We report that the shear stress–mediated remodeling of the KIF network is facilitated by a twofold increase in the dynamic exchange rate of KIF subunits, which is regulated in a PKC ζ and 14-3-3–dependent manner. PKC ζ phosphorylates K18pSer33, and this is required for the structural reorganization because the KIF network in A549 cells transfected with a dominant negative PKC ζ, or expressing the K18Ser33Ala mutation, is unchanged. Blocking the shear stress–mediated reorganization results in reduced cellular viability and increased apoptotic levels. These data suggest that shear stress mediates the phosphorylation of K18pSer33, which is required for the reorganization of the KIF network, resulting in changes in mechanical properties of the cell that help maintain the integrity of alveolar epithelial cells.

scholarly journals Determinants of plasma membrane wounding by deforming stress

2010 ◽  
Vol 299 (6) ◽  
pp. L826-L833 ◽  
Author(s):  
Richard A. Oeckler ◽  
Won-Yeon Lee ◽  
Mun-Gi Park ◽  
Othmar Kofler ◽  
Deborah L. Rasmussen ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cells ◽  
Optical Tweezers ◽  
Cellular Response ◽  
Ex Vivo ◽  
Experimental Models ◽  
Alveolar Epithelial Cells ◽  
Interfacial Stress ◽  
Alveolar Epithelial ◽  
Adhesive Interactions

Once excess liquid gains access to air spaces of an injured lung, the act of breathing creates and destroys foam and thereby contributes to the wounding of epithelial cells by interfacial stress. Since cells are not elastic continua, but rather complex network structures composed of solid as well as liquid elements, we hypothesize that plasma membrane (PM) wounding is preceded by a phase separation, which results in blebbing. We postulate that interventions such as a hypertonic treatment increase adhesive PM-cytoskeletal (CSK) interactions, thereby preventing blebbing as well as PM wounds. We formed PM tethers in alveolar epithelial cells and fibroblasts and measured their retractive force as readout of PM-CSK adhesive interactions using optical tweezers. A 50-mOsm increase in media osmolarity consistently increased the tether retractive force in epithelial cells but lowered it in fibroblasts. The osmo-response was abolished by pretreatment with latrunculin, cytochalasin D, and calcium chelation. Epithelial cells and fibroblasts were exposed to interfacial stress in a microchannel, and the fraction of wounded cells were measured. Interventions that increased PM-CSK adhesive interactions prevented blebbing and were cytoprotective regardless of cell type. Finally, we exposed ex vivo perfused rat lungs to injurious mechanical ventilation and showed that hypertonic conditioning reduced the number of wounded subpleural alveolus resident cells to baseline levels. Our observations support the hypothesis that PM-CSK adhesive interactions are important determinants of the cellular response to deforming stress and pave the way for preclinical efficacy trials of hypertonic treatment in experimental models of acute lung injury.

scholarly journals Hyperoxia alters the mechanical properties of alveolar epithelial cells

2012 ◽  
Vol 302 (12) ◽  
pp. L1235-L1241 ◽  
Author(s):  
Esra Roan ◽  
Kristina Wilhelm ◽  
Alex Bada ◽  
Patrudu S. Makena ◽  
Vijay K. Gorantla ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Ventilation ◽  
Elastic Modulus ◽  
Epithelial Cells ◽  
Lung Injury ◽  
Alveolar Epithelial Cells ◽  
Cyclic Stretch ◽  
Cell Deformability ◽  
Element Analysis ◽  
Alveolar Epithelial

Patients with severe acute lung injury are frequently administered high concentrations of oxygen (>50%) during mechanical ventilation. Long-term exposure to high levels of oxygen can cause lung injury in the absence of mechanical ventilation, but the combination of the two accelerates and increases injury. Hyperoxia causes injury to cells through the generation of excessive reactive oxygen species. However, the precise mechanisms that lead to epithelial injury and the reasons for increased injury caused by mechanical ventilation are not well understood. We hypothesized that alveolar epithelial cells (AECs) may be more susceptible to injury caused by mechanical ventilation if hyperoxia alters the mechanical properties of the cells causing them to resist deformation. To test this hypothesis, we used atomic force microscopy in the indentation mode to measure the mechanical properties of cultured AECs. Exposure of AECs to hyperoxia for 24 to 48 h caused a significant increase in the elastic modulus (a measure of resistance to deformation) of both primary rat type II AECs and a cell line of mouse AECs (MLE-12). Hyperoxia also caused remodeling of both actin and microtubules. The increase in elastic modulus was blocked by treatment with cytochalasin D. Using finite element analysis, we showed that the increase in elastic modulus can lead to increased stress near the cell perimeter in the presence of stretch. We then demonstrated that cyclic stretch of hyperoxia-treated cells caused significant cell detachment. Our results suggest that exposure to hyperoxia causes structural remodeling of AECs that leads to decreased cell deformability.

scholarly journals Determination of the viscoelastic properties of a single cell cultured on a rigid support by force microscopy

Nanoscale ◽  
2018 ◽  
Vol 10 (42) ◽  
pp. 19799-19809 ◽  
Author(s):  
Pablo D. Garcia ◽  
Ricardo Garcia
Keyword(s):  
Mechanical Properties ◽  
Single Cell ◽  
Viscoelastic Properties ◽  
Living Cells ◽  
Central Issue ◽  
Rigid Support ◽  
Force Microscopy ◽  
The Relationship

Understanding the relationship between the mechanical properties of living cells and physiology is a central issue in mechanobiology.

scholarly journals Optical trapping in vivo: theory, practice, and applications

Nanophotonics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 1023-1040 ◽  
Author(s):  
Itia A. Favre-Bulle ◽  
Alexander B. Stilgoe ◽  
Ethan K. Scott ◽  
Halina Rubinsztein-Dunlop
Keyword(s):  
Mechanical Properties ◽  
Optical Tweezers ◽  
Laser Light ◽  
Living Cells ◽  
Cellular Systems ◽  
Free Swimming ◽  
Quantitative Measurements ◽  
Swimming Bacteria ◽  
Fluorescent Nanodiamonds

AbstractSince the time of their introduction, optical tweezers (OTs) have grown to be a powerful tool in the hands of biologists. OTs use highly focused laser light to guide, manipulate, or sort target objects, typically in the nanoscale to microscale range. OTs have been particularly useful in making quantitative measurements of forces acting in cellular systems; they can reach inside living cells and be used to study the mechanical properties of the fluids and structures that they contain. As all the measurements are conducted without physically contacting the system under study, they also avoid complications related to contamination and tissue damage. From the manipulation of fluorescent nanodiamonds to chromosomes, cells, and free-swimming bacteria, OTs have now been extended to challenging biological systems such as the vestibular system in zebrafish. Here, we will give an overview of OTs, the complications that arise in carrying out OTs in vivo, and specific OT methods that have been used to address a range of otherwise inaccessible biological questions.

Alveolar epithelial cells type II show a high sensitivity to cigarette smoke extract

Pneumologie ◽  
2014 ◽  
Vol 68 (06) ◽  
Author(s):  
S Seehase ◽  
B Baron-Luehr ◽  
C Kugler ◽  
E Vollmer ◽  
T Goldmann
Keyword(s):  
Epithelial Cells ◽  
Cigarette Smoke ◽  
High Sensitivity ◽  
Cigarette Smoke Extract ◽  
Alveolar Epithelial Cells ◽  
Type Ii ◽  
Alveolar Epithelial
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