By focusing on the acoustic properties of target cells, the new device allows scientists to carefully sort them, even if they're the same size. It's made up of a tiny channel of fluid that vibrates at a low frequency. A compound called iodixanol is added to the water that moves through the channel, creating a density gradient in the liquid, with the densest liquid at the center.
Under normal circumstances, that gradient would eventually collapse, but the acoustic force from the constant vibrations keeps it stable, allowing researchers to use the channel as a tool for sorting cells. As they enter the channel, the cells move sideways, stopping only when they reach a density that matches with the acoustic properties of their contents and structure.
The system has practical uses, allowing for the creation of small, handheld devices capable of completing complete blood count (CBC) tests much more quickly than current methods allow. Normally, such analysis requires samples to be sent to a lab for detailed analysis, working out the number of red and different white blood cells present.
Results are already positive from lab testing, with the team able to distinguish between monocytes, lymphocytes and neutrophils, which are all types of white blood cell. The readings were clear, despite neutrophils and monocytes being very similar in size.
It's even possible that uses for the device might go beyond a new method for conducting blood tests. During the study, the researchers were able to distinguish between different types of tumor cell, meaning that the method might be useful in monitoring cancer progression.
The researchers published their work in the journal Nature Communications.