Simulating Force Response at Cellular Junctions: Desmoplakin as a Molecular Force Sensor?

Cancer deaths are mostly caused by the metastasis of the malignant cells, not by the primary tumor itself. During metastasis, cancer cells detach from the primary tumor, spread to different tissues via blood circulation or lymph system, and reattach to invade new tissues and organs. In this project, we hypothesize that cancer cells manage their invasion by changing their surface adhesivity. To study the cell surface adhesivity, a novel and versatile microelectromechanical systems (MEMS) force sensor is developed to quantify the strength of adhesion between living cancer cells and a probe. The Silicon sensors consist of a probe and 2 flexible cantilever beams, while the probe is used to contact the cancer cell and the flexible beams are used to measure the cell force response in the range from nN to uN. The spring constant of the sensor is 14 nN/ μm. Our results demonstrate that the aggressive HCT-8 cells (from human colon adenocarcinoma) show high nonspecific adhesivity when they aggregate into cell islands, and low surface non-specific adhesivity after they disassociate from the cell islands. The surface adhesivity of less aggressive Caco-2 cells (from human colon carcinoma) and normal MA104 cell (from monkey kidney) are found to be lower than that of before-disassociation HCT-8 cells. Furthermore, the adhesion force response of cancer cells is found to show 2-slope force behavior, which is different from previous results of focal-adhesion detachment experiments. The 2-stage force bearing model is proposed to interpret the underlying mechanism.

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An Analysis of Force Response by Using Spectrogram

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.781.466 ◽

2015 ◽

Vol 781 ◽

pp. 466-470

Author(s):

Napol Varachitchai ◽

Chowarit Mitsantisuk

Keyword(s):

Force Sensor ◽

High Accuracy ◽

Human Operator ◽

Flexible Systems ◽

Force Response ◽

Bilateral Control ◽

Accuracy And Precision ◽

Robot Systems ◽

Haptic Technology

In haptic technology, robot has to contact with objects and human operator. The robot systems must be flexible systems, high accuracy and precision during the operation for safe the human operator. So, analysis of the force response is a necessary ability to design the controller of the robot systems. This paper proposes a methodology to analyze force response by mean of spectrogram analysis. The master-slave robot based on bilateral control is used by human operator. Disturbance Observe (DOB) is used to estimate the force response instead of force sensor to improve the performance of the whole system. Finally, force response is analyzed by spectrogram. The availability of the proposed method is shown in an experiment.

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Faculty Opinions recommendation of Myosin I can act as a molecular force sensor.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1116528.575510 ◽

2008 ◽

Author(s):

David Sept

Keyword(s):

Force Sensor ◽

Myosin I ◽

Molecular Force

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Force Response of Single Living Cells Due to Localized Deformation (Invited Talk)

Microelectromechanical Systems ◽

10.1115/imece2002-32808 ◽

2002 ◽

Author(s):

T. Saif ◽

C. Sager ◽

S. Coyer

Keyword(s):

Mechanical Response ◽

Single Crystal Silicon ◽

Fibroblast Cell ◽

Force Sensor ◽

Local Deformation ◽

Force Response ◽

Localized Deformation ◽

Crystal Silicon ◽

Micro Electro Mechanical Systems ◽

Adhesion Site

We present a method for measuring the mechanical response of a single cell in-situ when local deformation is applied at an adhesion site(s) by a functionalized MEMS (Micro Electro Mechanical Systems) force sensor with pN – nN force resolution, and with force and displacement ranges of 100s of nNs and μms. The force sensor is a micro mechanical cantilever beam made of single crystal silicon (SCS), coated by a thin layer of Fibronectin, an extra cellular matrix (ECM) protein, to activate cell adhesion. The end of the beam is brought in contact with a cell to form the adhesion site(s). The cantilever is then moved away from the cell to locally deform it. The force on the cell is measured from the deformation of the cantilever until the adhesion sites fails. We demonstrate the method by deforming several endothelial and fibroblast cells. Force response of the fibroblast cell shows linear behavior.

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