By combining microfabricated cantilevers and magnetic nanowire technology to create independent, nanoscale sensors, the study showed that cells respond to outside forces and demonstrated a dynamic biological relationship between cells and their environment.
The study also revealed that cells sense force at a single adhesion point that leads not to a local response but to a remote response from the cell’s internal forces, akin to tickling the cell’s elbow and watching the knee kick.
“The cell senses the force that we apply and adjusts its own internal forces to compensate,” Chris Chen, an associate professor in the Department of Bioengineering in the School of Engineering and Applied Science at Penn, said. “This suggests that either the cell’s cytoskeleton dictates the reaction or the cell organizes a biochemical response. In either instance, cells are adapting at the microscale.”
The findings prove useful to more than just an understanding of the mechanics of single cells. Physical forces play a strong role in how whole tissue grows and functions. Using the Penn system, researchers could monitor for differences in how forces are sensed or generated in normal and diseased cells. This could lead to new therapeutic drug targets and to methods for modifying how cells interact with each other.
To study the cell’s biomechanical response to forces, Chen and his team applied force to each cell using microfabricated arrays of magnetic posts containing cobalt nanowires interspersed amongst an array of non-magnetic posts. In the magnetic field, the posts with nanowires applied an external force to cells cultured on the tops of the posts. Nonmagnetic posts acted as sensors in which traction forces in each cell were measured. Recording the traction forces in response to such force stimulation revealed two responses: a sudden loss in contractility that occurred within the first minute of stimulation or a gradual decay in contractility over several minutes.
For both types of responses, the subcellular distribution of loss in traction forces was not confined to locations near the actuated micropost or uniformly across the whole cell but instead occurred at discrete locations along the cell periphery. Together, these data suggest that cells actively adjust their internal tension to mechanical forces arising in their microenvironment and reveal an important dynamic biological relationship between external and internal forces.
Mechanical forces contribute to many cellular functions, including changes in gene expression, proliferation and differentiation.
Applying shear or tensile stresses to cells in culture, for example, can induce changes in adhesion regulation, intracellular signaling and cell function much like internal forces do. The similarities in cellular responses to external and internal forces have led to the suggestion that both types of forces may use shared mechanotransduction pathways to convert mechanical stimuli into biochemical signals. While externally applied and internally generated forces may act independently on cells, the University of Pennsylvania team postulated and then showed that they are coupled.
Jordan Reese | EurekAlert!
What happens in the cell nucleus after fertilization
06.12.2016 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
06.12.2016 | Materials Sciences
06.12.2016 | Medical Engineering
06.12.2016 | Power and Electrical Engineering