Mechanical fatigue is the process by which materials fail after being subjected to repeated stress. In the human body, mechanical fatigue can occur in cells and tissues that are subjected to repeated stress, such as the joints, heart, and blood vessels.
The new method, called "nanoindentation fatigue testing," allows researchers to measure the mechanical properties of individual cells and how they change over time when subjected to repeated stress. The researchers used this method to test the mechanical properties of human mesenchymal stem cells, which are cells that can differentiate into a variety of other cell types.
The researchers found that human mesenchymal stem cells exhibited a decrease in stiffness and an increase in hysteresis, which is a measure of the energy lost during a loading-unloading cycle, when subjected to repeated stress. This suggests that mechanical fatigue can lead to damage in human cells, which could contribute to the development of conditions such as osteoarthritis and heart disease.
The new method could be used to study the mechanical properties of other types of cells and tissues, and to identify potential therapeutic targets for conditions caused by mechanical fatigue.
"This new method provides a powerful tool for studying the mechanical properties of individual cells and how they change over time," said lead author James R. Nairn, a professor of materials science and engineering at the University of California, San Diego. "This information could lead to new treatments for conditions such as osteoarthritis and heart disease."
In addition to Nairn, the study was co-authored by researchers from the University of California, Berkeley, and the Mayo Clinic.
