Researchers are perpetually interested in characteristics of cells and what we can learn from them. Recently, a team from Canada’s Université de Montréal came up with a unique procedure they call “cell quake elastography” to determine the mechanical properties of cells based on the vibrations within them.
Why Is This Significant?
The knowledge that cells have fluctuating elasticity is not new. However, Pol Grasland-Mongrain, the lead author of this study clarifies it has previously been difficult to measure that feature of cells. Techniques used to do so include cell deformation and Brillouin scattering.
However, those options take more than 30 minutes to perform. In contrast, this new method achieves the goal in milliseconds. Any way of measuring cell vibrations that requires a significant amount of time is impractical because it could cause scientists to miss pertinent events like neuron stimulations and the death of cells.
An Achievement Made With Relatively Simple Equipment
Many people would understandably think measuring cell vibrations in this way so quickly would require extraordinarily advanced and hard-to-acquire equipment. However, the scientists only relied on a standard microscope, micropipettes and a high-speed camera capable of capturing 200,000 frames per second.
They chose living cells from mice that are about 80 microns in diameter, which is considered large and easier to see than some smaller varieties. Then, they made the cells from the mice vibrate at 15,000 cycles per second using a micropipette piezoelectric actuator.
After snapping images of the effects with the camera, the researchers analyzed the vibrations with optical flow algorithms that measured the amount of displacement within the cells — these formulas were initially developed for use within ultrasound applications. Other industries use vibrations for research, too, so the scientists had some traditional applications to try for their own needs.
However, they still needed to go further to create a map of elasticity inside the cells based on the vibration statistics. To do so, the team depended on a noise correlation technique that seismologists use when they evaluate earthquake vibrations to study subterranean rock composition.
With the help of shear wave elastography, which can perform micrometer-scale measurements, the scientists could send a wave into the cell and notice the wave’s speed was proportional to the elasticity present in the cell’s components. They realized it was possible to measure the elasticity of an entire cell by determining the how fast the vibrations occurred in time and space.
Potential Future Applications for This Research
This study, which appeared in the Proceedings of the National Academy of Sciences (PNAS) journal, involved introducing a mycotoxin called Cytochalasin B into the mouse cells. After doing that and using their vibrational measuring process, the scientists found the substance softened the interior of the cell, and they confirmed the change with their method.
Previous research that studied cell interior elasticity through atomic force microscopy found differences in healthy cells versus cancerous ones. With these new findings, scientists are hopeful they can continue to explore the interior of cells in this manner and understand how diseases and treatments impact them. They also say it’s possible to perform 3-D cell mapping by merely changing the focal depth of the microscope.
The team that carried out this recent study clarifies that the use of phase-contrast optical methods could provide better resolution and perhaps improve estimations about the amount of displacement by looking at phase information.
They also said results could feasibly be generated using a cheaper camera at a slower speed by capturing synchronized images and repeating them, in addition to taking pictures with greater delays between each shot.
On top of becoming a preferred method for mapping biomechanical properties due to its significantly faster speed compared to other options, the scientists envision this technique potentially making it easier to study dynamic cellular activities and discovering characteristics that were not detectable in the past.
This research is a strong example of how techniques usually applied to other fields of study — seismology in this case — can be advantageous elsewhere, too. And although these cell mapping improvements will likely be most helpful the realm of biology, people in other sectors might benefit from them, as well.
Written by Kayla Matthews, Productivity Bytes.