[Coherent phase microscopy: a new method of identification of intracellular structures based on their optical and...

A new method for the identification of intracellular structures of a living cell and obtaining the quantitative parameters characterizing these structures by means of coherent phase microscopy is proposed. The method is based on the analysis of the histogram of a cell phase image and its decomposition by phase height levels. In the spherical and cylindrical approximation of the cell, the method makes it possible to separate the contributions of phase-contrast intracellular structures to the integral refractive index of the whole cell. The calculation of refractive indices of intracellular structures is illustrated on a two-component model of a spherical cell. The possibility of determining the refractive indices of cellular organelles was shown by an example of cyanobacterium Anabaena variabilis ATCC 29413 cells and Cancer mammae breast cancer cells. Three most contrast cellular structures in the phase images of the cells were identified, and their refractive indices were determined. For Anabaena variabilis cells, these structures were the cell wall ( = 1.39), tylakoids ( = 1.47), and the nucleoid ( = 1.58); for breast cancer cells, these were the cytoplasm ( = 1.34), the nucleus ( = 1.36), and the nucleolus ( = 1.44). Using this method is possible to identify phase-contrast intracellular structures and calculate their refractive indices. This enables one to follow morphofunctional changes of not only the whole cell but also its individual organelles.