scholarly journals Ex-Vivo Force Spectroscopy of Intestinal Mucosa Reveals the Mechanical Properties of Mucus Blankets

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Javier Sotres ◽  
Skaidre Jankovskaja ◽  
Kristin Wannerberger ◽  
Thomas Arnebrant
Keyword(s):  
Mechanical Properties ◽  
Intestinal Mucosa ◽  
Ex Vivo ◽  
Force Spectroscopy

scholarly journals Biomechanical Characterization of Endothelial Cells Exposed to Shear Stress Using Acoustic Force Spectroscopy

2021 ◽  
Vol 9 ◽  
Author(s):  
Giulia Silvani ◽  
Valentin Romanov ◽  
Charles D. Cox ◽  
Boris Martinac
Keyword(s):  
Mechanical Properties ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Actin Filament ◽  
Force Spectroscopy ◽  
Shear Stresses ◽  
Cell Periphery ◽  
Static Conditions ◽  
Cells Cultured ◽  
Cell Cell

Characterizing mechanical properties of cells is important for understanding many cellular processes, such as cell movement, shape, and growth, as well as adaptation to changing environments. In this study, we explore the mechanical properties of endothelial cells that form the biological barrier lining blood vessels, whose dysfunction leads to development of many cardiovascular disorders. Stiffness of living endothelial cells was determined by Acoustic Force Spectroscopy (AFS), by pull parallel multiple functionalized microspheres located at the cell-cell periphery. The unique configuration of the acoustic microfluidic channel allowed us to develop a long-term dynamic culture protocol exposing cells to laminar flow for up to 48 h, with shear stresses in the physiological range (i.e., 6 dyn/cm2). Two different Endothelial cells lines, Human Aortic Endothelial Cells (HAECs) and Human Umbilical Vein Endothelial Cells (HUVECs), were investigated to show the potential of this tool to capture the change in cellular mechanical properties during maturation of a confluent endothelial monolayer. Immunofluorescence microscopy was exploited to follow actin filament rearrangement and junction formation over time. For both cell types we found that the application of shear-stress promotes the typical phenotype of a mature endothelium expressing a linear pattern of VE-cadherin at the cell-cell border and actin filament rearrangement along the perimeter of Endothelial cells. A staircase-like sequence of increasing force steps, ranging from 186 pN to 3.5 nN, was then applied in a single measurement revealing the force-dependent apparent stiffness of the membrane cortex in the kPa range. We also found that beads attached to cells cultured under dynamic conditions were harder to displace than cells cultured under static conditions, showing a stiffer membrane cortex at cell periphery. All together these results demonstrate that the AFS can identify changes in cell mechanics based on force measurements of adherent cells under conditions mimicking their native microenvironment, thus revealing the shear stress dependence of the mechanical properties of neighboring endothelial cells.

scholarly journals Ex vivo infiltration of fibroblasts into the tendon deteriorates the mechanical properties of tendon fascicles but not those of tendon bundles

2007 ◽  
Vol 22 (1) ◽  
pp. 120-126 ◽  
Author(s):  
Yasunari Ikema ◽  
Harukazu Tohyama ◽  
Ei Yamamoto ◽  
Fuminori Kanaya ◽  
Kazunori Yasuda
Keyword(s):  
Mechanical Properties ◽  
Ex Vivo

The mechanics of single cross-links which mediate cell attachment at a hydrogel surface

Nanoscale ◽  
2019 ◽  
Vol 11 (24) ◽  
pp. 11596-11604 ◽  
Author(s):  
Arzu Çolak ◽  
Bin Li ◽  
Johanna Blass ◽  
Kaloian Koynov ◽  
Aranzazu del Campo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Adhesion ◽  
Cell Attachment ◽  
Force Spectroscopy ◽  
Single Cross ◽  
Mediate Cell Adhesion ◽  
Cross Links ◽  
Hydrogel Surface ◽  
Mediate Cell

The mechanical properties of single cross-links which mediate cell adhesion are explored by force spectroscopy.

scholarly journals Harmonic motion imaging of human breast masses: an in vivo clinical feasibility

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Niloufar Saharkhiz ◽  
Richard Ha ◽  
Bret Taback ◽  
Xiaoyue Judy Li ◽  
Rachel Weber ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Malignant Tumors ◽  
Ex Vivo ◽  
Benign Tumors ◽  
Cancerous Tissue ◽  
Breast Masses ◽  
Harmonic Motion ◽  
Harmonic Motion Imaging ◽  
Motion Imaging

Abstract Non-invasive diagnosis of breast cancer is still challenging due to the low specificity of the imaging modalities that calls for unnecessary biopsies. The diagnostic accuracy can be improved by assessing the breast tissue mechanical properties associated with pathological changes. Harmonic motion imaging (HMI) is an elasticity imaging technique that uses acoustic radiation force to evaluate the localized mechanical properties of the underlying tissue. Herein, we studied the in vivo feasibility of a clinical HMI system to differentiate breast tumors based on their relative HMI displacements, in human subjects. We performed HMI scans in 10 female subjects with breast masses: five benign and five malignant masses. Results revealed that both benign and malignant masses were stiffer than the surrounding tissues. However, malignant tumors underwent lower mean HMI displacement (1.1 ± 0.5 µm) compared to benign tumors (3.6 ± 1.5 µm) and the adjacent non-cancerous tissue (6.4 ± 2.5 µm), which allowed to differentiate between tumor types. Additionally, the excised breast specimens of the same patients (n = 5) were imaged post-surgically, where there was an excellent agreement between the in vivo and ex vivo findings, confirmed with histology. Higher displacement contrast between cancerous and non-cancerous tissue was found ex vivo, potentially due to the lower nonlinearity in the elastic properties of ex vivo tissue. This preliminary study lays the foundation for the potential complementary application of HMI in clinical practice in conjunction with the B-mode to classify suspicious breast masses.

scholarly journals Atomic Force Microscopy as a Tool for the Investigation of Living Cells

Medicina ◽  
2013 ◽  
Vol 49 (4) ◽  
pp. 25 ◽  
Author(s):  
Inga Morkvėnaitė-Vilkončienė ◽  
Almira Ramanavičienė ◽  
Arūnas Ramanavičius
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
High Resolution ◽  
Force Spectroscopy ◽  
Living Cells ◽  
Fixation Method ◽  
Cell Preparation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Cell Fixation

Atomic force microscopy is a valuable and useful tool for the imaging and investigation of living cells in their natural environment at high resolution. Procedures applied to living cell preparation before measurements should be adapted individually for different kinds of cells and for the desired measurement technique. Different ways of cell immobilization, such as chemical fixation on the surface, entrapment in the pores of a membrane, or growing them directly on glass cover slips or on plastic substrates, result in the distortion or appearance of artifacts in atomic force microscopy images. Cell fixation allows the multiple use of samples and storage for a prolonged period; it also increases the resolution of imaging. Different atomic force microscopy modes are used for the imaging and analysis of living cells. The contact mode is the best for cell imaging because of high resolution, but it is usually based on the following: (i) image formation at low interaction force, (ii) low scanning speed, and (iii) usage of “soft,” low resolution cantilevers. The tapping mode allows a cell to behave like a very solid material, and destructive shear forces are minimized, but imaging in liquid is difficult. The force spectroscopy mode is used for measuring the mechanical properties of cells; however, obtained results strongly depend on the cell fixation method. In this paper, the application of 3 atomic force microscopy modes including (i) contact, (ii) tapping, and (iii) force spectroscopy for the investigation of cells is described. The possibilities of cell preparation for the measurements, imaging, and determination of mechanical properties of cells are provided. The applicability of atomic force microscopy to diagnostics and other biomedical purposes is discussed.

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