A particle self-aligning, focusing, and electric impedance micro-cytometer device for label-free single cell morphology discrimination and yeast budding analysis

Microfluidic electric impedance flow cytometry (IFC) devices have been applied in single cell analysis, such as cell counting, volume discrimination, cell viability, etc. A cell’s shape provides specific information about cellular physiological and pathological conditions, especially in microorganisms such as yeast. In this study, the particle orientation focusing was theoretically analyzed and realized by hydrodynamics. The pulse width (passing time for the particles) of the conductance signal was used to discriminate particle shapes. Spherical and rod-shaped particles with similar volumes/lengths were differentiated by the IFC device, using the impedance pulse parameters of the events. Then, typical late-budding, early budding, and unbudded yeast cells were distinguished by the width, amplitude, and ratio of width to amplitude (R) of the impedance pulse. The pulse amplitude and the R combination gate for identifying the late-budding yeast was estimated through the statistic results. Using the gate, the ...