Candida Cell Heterogeneity Measured 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 and C. albicans, which are two of the most important Candida yeasts that cause candidemia disease. The obtained scatter plots of cell permittivity for both the species show a colinear relationship for cells of different volumes, which indicates a largely conserved cell molecular composition profile despite heterogeneous cell sizes. We also apply microwave flow cytometer to measure antifungal drug effect on C. tropicalis and C. albicans cell population and observe that drugs induce significant heterogeneity increase. The results show that microwave flow cytometry is a promising new method for high throughput and noninvasive characterization of cell heterogeneity. More work is needed, including the determination of biological significance of the observed microwave heterogeneity.