Scientists from the University of Exeter’s Living Systems Institute have developed a flow cytometer that can move individual cells between “virtually” separate microfluidic channels — thereby exposing them to a substance that can induce a cellular response. With the instrument, called the functional phenotype flow cytometer (FPFC), the scientists were able to sort cells by their function and by the strength of their response, in greater granularity than previously possible. The examination and separation of single cells based on their response to stimuli could improve personalized medicine by detecting whether a specific drug is likely to be effective for a patient before administration. The team’s flow cytometer is also poised to increase understanding of human molecular mechanisms, the researchers reported. In an implementation described in a published paper, the researchers describe how the device uses intracellular fluorescence as a readout, incubates cells for 75 seconds, and operates at a throughput that enables the profiling and sorting of hundreds of cells within a few hours. Before they entered the cells into the device, the researchers exposed the cells to a biological reagent solution, which means the brighter their fluorescent glow, the stronger their response. The FPFC performs three consequent cell processing steps on a microfluidic chip: It monitors the individual cell response across the population, it incubates cells with a stimulus, and it sorts the responsive cells in real time. The device can profile and sort hundreds of cells, depending on their functional response, and, crucially, can still detect the strength of each cell’s response. “Our device allows cells to be sorted into subgroups in a far more refined way than ever before. We can see not only their function, but how effective it is,” said Catalin Chimerel, who led the research. “We are excited to see how this research will develop, with a longer-term aim of translation into commercial use.” The University of Exeter has filed a patent application on the technology and seeks a commercial partner to ultimately move from proof of concept toward commercialization. “On a basic level, this has the potential to help us make huge advance into understanding our own cellular makeup,” Chimerel said. “An obvious application is in testing drug response — by exposing the patient’s cells to a drug in our device, we will get a very good indication of whether it will prove effective, meaning we have a much better chance of choosing the right drug first time, improving care, and reducing unnecessary side effects.” The research was published in Advanced Biology (www.doi.org/10.1002/adbi.202100220).