Skip to content

Cells Sorted out with Sound

Researchers have asked, what do cells sound like? This topic may be believed not to have an answer, but there is. The answer could change the way research may be conducted in the future.

A microfluidic device that was recently developed can distinguish cells by the size, electrical properties, and deformability according to their sound properties. The response to the sound waves is due to the compressibility and the denseness of the cells. This is done to separate the cells of similar size which assists in making the chemical labels unnecessary.

How to Sort Cells by Sound

The microfluidic channel trembles at low frequencies. As the cells flow through the channels, they are moved into a certain position by the acoustic forces depending on how they interact to the vibration.

If the cells float through the channel on water, most of them cluster at the center due to the cells being denser than water. Researchers can add the compound iodixanol which will create a denser gradient medium with the channel to try and prevent the clusters.


The small vibrations that are applied result in acoustic forces that maintain that gradient position. The cells are forced to move sideways due to the gradient density while they flow along the channel until reaching the correct section. If the liquid is made very dense in the middle and less dense on the sides, then the cells will move into the required positions according to the environment. This is believed by Joel Voldman who is an MIT professor in the fields of electrical engineering and computer science.

Applications for Acoustic Cell Sorting

With this type of knowledge and experiments, the technique could possibly lead to the creation of a handheld machine that will be capable of providing quick test results for a person’s complete blood count. The test that uses the current to determine the same result requires blood samples that will need to send to a doctor’s lab for analysis. The test usually shows how many red blood cells there are and what different kinds of white blood cells are visible in a patient’s bloodstream. The lab technician would need to do a complete labeling of cells that with this device will no longer be necessary.

The method can divide the different kinds of white blood cells into neutrophils, monocytes, and lymphocytes which can be differentiated from each other. The Monocytes and the neutrophils have a similar size that would make it difficult to distinguish normally, but that is not an issue for the microfluidic device.

An added feature is that the device could possibility isolate tumor cells from the patient’s sample and allow a doctor to monitor any cancer progression as a result. So far, the research has soon that this method could also distinguish the different types of tumor cells that are present based on their acoustic properties. Certain types of cancers and other diseases could, therefore, be picked up and diagnosed by this method.