Microfluidics is a multidisciplinary field that is responsible for the development of lab-on-a-chip technology. Microfluidic devices can be used to quickly analyze cells based on various characteristics like cell size, or electrical properties. These devices have been used to create organ-on-a-chip systems that can be used for testing medication effects, and diagnose ebola.
Now a team from MIT has developed a new way to classify and sort cells using sound waves and microfluidics. Sound waves will affect cells differently depending on how dense and compressible the cells are. This new sound-based technology could lead to the creation of a handheld device to conduct a complete blood count (CBC). A CBC test typically requires samples to be sent to a lab for analysis. According to a paper written by MIT electrical engineering and computer science professor, Joel Voldman, “You could do a complete blood count that doesn’t require any labeling of the cells.”
How does it work?
The new device they created has a microfluidic channel that vibrates at a low frequency. As the cells flow through the channel, they will get pushed to certain areas depending on how they interact with the sound waves. A compound called iodixanol is added to the water in the channel, which creates a density gradient in the liquid. The densest liquid will be in the center, and less dense at the edges.
Researchers are able to use the channel as a tool to sort cells. As cells enter the channel, they will move until they find a density that matches their acoustic properties. Researchers using this method have been able to distinguish between three different types of white blood cells – monocytes, lymphocytes, and neutrophils. During the study, researchers also were able to differentiate between different types of tumor cells.
What’s the big deal?
This new method of analyzing cells has two main benefits. The first is that this new method is able to sort cells that are of similar size since acoustic properties are based on cell content and structure, but independent of size. This allowed researchers to clearly identify the monocytes from neutrophils, even though they are very close in size. The second benefit of this new method is that there are no biomarkers, chemical labels, or cell alteration.
This sound-based technology coupled with microfluidics will have further applications in the medical field. Beyond analyzing red and white blood cells, it could be used to isolate tumor cells from a patient’s blood sample, helping to monitor the progression of cancer. Eventually, the technology could be used in very important medical applications such as filtering cancerous cells from the bloodstream.