Measuring yeast cell heterogeneity with a microwave flow cytometer

Heterogeneity is an important property of a cell population. It is an intrinsic driving force behind biological evolution and a main challenge for effective disease treatment, such as precision solid cancer therapy. Various “omics” methods, mass spectroscopy-based techniques, and flow cytometry have been developed for cell heterogeneity characterization. But current methods are either low throughput or invasive. In this work, we develop a simple microwave flow cytometer to measure single C. tropicalis, one of the most important Candida yeasts that cause candidemia disease. The obtained scatter plots of cell permittivity show a colinear relationship for cells of different volumes, which indicates a largely conserved cellular constituent profile despite heterogeneous cell sizes. Variations of cell molecular composition, i.e., heterogeneity, are omnipresent, but at a magnitude much smaller than size heterogeneity. The results show that microwave flow cytometry is a promising new method for high throughput and noninvasive characterization of cell heterogeneity.