A new electromagnetic device that enables high-resolution measurements of a wide range of soft biological tissues has set a new standard for accuracy in the field of mechanobiology, the researchers said. This method allows mechanical testing of tissue on the size of human biopsy specimens, making it particularly relevant for studies of human disease.
The body’s soft tissues exhibit a wide range of mechanical properties, such as stiffness and strength, that are essential for their functioning. For example, the tissues of the digestive tract are soft to allow food to pass through and be digested, while tendons are relatively tougher to transfer force from muscles to bones allowing us to move.
The ability to accurately measure the mechanical properties of these tissues, which undergo change during developmental processes or due to disease, has profound implications for the fields of biology and medicine. Methods for measuring these properties are currently inadequate, and their accuracy and reliability are still limited—until now.
New research involving researchers from the University of Cambridge and the MIT Institute for Medical Engineering and Science (IMES) results in a device based on magnetic actuation and optical sensing, allowing live imaging of tissues under an inverted microscope. In this way, insights into tissue behavior under mechanical forces can be gained at both the cellular and molecular levels. The results are reported in the journal Science advances.
The electromagnet exerts a pulling force on the tissue sample fixed to the device, while the optical system measures the sample’s change in size or shape.
“One of the most important requirements for mechanical testing of soft biological tissues is the need to mimic the physiological conditions of the biological sample (such as temperature and nutrients) as closely as possible, in order to keep the tissue alive and maintain its biomechanical properties,” said Dr. Thierry Savin, Associate Professor of Bioengineering, who led the research team. “To this end, we designed a transparent mounting chamber to measure the mechanical properties of tissues—at the millimeter scale—in their native physiological and chemical environment. The result is a more versatile, accurate, and robust device that shows high reliability and reproducibility.”
To directly evaluate the performance of their electromagnetic device, the researchers conducted a study of the biomechanics of the mouse esophagus and its constituent layers. The esophagus is the muscular tube that connects the throat to the stomach and is made up of multiple layers of tissue. The researchers used the device to perform the first biomechanical investigation of each of the three individual layers of mouse esophageal tissue. Their findings showed that esophagus behaves like a three-layer composite material similar to that commonly used in many engineering applications. To the researchers’ knowledge, these are the first results gained of the mechanical properties of each individual layer of the esophagus.
said Dr Adrien Hallou, a postdoctoral fellow at the Wellcome Trust/Cancer Research UK Gurdon Institute. “We hope that this device will eventually become the new standard in the field of tissue biomechanics, providing a standardized data set for characterizing murine and human soft tissue mechanics across the board.”
Luca Rosalia, PhD candidate at IMES, added: “By analyzing the biomechanics of healthy tissues and their changes as they occur during disease, our device can eventually be used to identify changes in tissue properties relevant to prognosis, thus becoming a valuable tool to inform clinical decisions.”
A magnetically actuated and optically sensor tensile test method for mechanical characterization of soft biological tissues
The date the article was published
January 11, 2023
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