Monitoring of the Budding Yeast Cell Cycle Using Electrical Parameters

Finding non-invasive and label-free techniques that allow real-time monitoring of living cells is a field of intensive research with first trials dating back to a century. Employing dielectric spectroscopy on biological materials has aided in deciphering many aspects of living cells, such as cell structure and physiology. In this paper, we studied the dielectric parameters of budding yeast cell suspension as they progressed through the cell cycle. This was done by measuring the capacitance-voltage profile as well as other electrical parameters of cells at different phases of the cell cycle. For this purpose, cells were initially synchronized at the G1 phase and then released in the culture media. Samples at different time points were taken, and both electrical and flow cytometry analyses were carried out. In this paper, we have measured the electrical parameters of the yeast cells as they progress through the cell cycle at very low frequencies, which is believed to preserve all the mechanisms of polarization in yeast cell suspensions. In addition, this allows us to observe electrical changes independent of initial cell numbers. The results reveal an incremental increase in the capacitance-voltage profile as cells progressed through the cell cycle. The capacitance-voltage profile could be used to determine the doubling time of the yeast cells. Studying the yeast doubling time is important in the real-time assessment of different strains/mutants in terms of their progress through the cell cycle and any potential differences between yeast strains. Electrical-based techniques are more sensitive to small changes that occur in cells, which cannot be traced by other methods such as fluorescence-activated cell sorting (FACS). Moreover, if such a technique, used in this paper, is integrated into a multiplexing system, which allows parallel and simultaneous runs, it could potentially be more powerful than FACS for offering real-time automated measurements of cell cycle progress, avoiding the lengthy processing time required by FACS.