Optical differential tomography method for measuring morphological and physiological parameters of erythrocytes

An overview of the application of optical tomography methods in the fi eld of biological and physicochemical research is given. The capabilities of existing methods are described. However, the capabilities of optical tomography in the study of cell biology have not yet been fully explored. At present, much attention is paid to the study of blood cells, in particular erythrocytes, using optical tomography. A method for studying the redistribution of hemoglobin molecules in single native erythrocytes with a change in the osmolarity of the medium has been developed. The method is based on the principles of differential optical tomography and its modifications. This method allows obtaining information on changes in morphological and physiological parameters of cells in real time without using exogenous labels as a contrast for visualization. An original algorithm for processing differential tomography data is proposed: restoration of phase images of individual erythrocytes. As a result of data processing, three-dimensional images of changes in the refractive index during two hours of exposure of the erythrocyte in a hypoosmolar medium are obtained. Several cell parameters, including morphology and dry mass of proteins, and their changes in the medium under conditions different from normal physiological conditions in vivo were calculated. Changes in cell morphology, a decrease in dry mass, and three-dimensional maps of intracellular hemoglobin distribution were obtained. It was found that significant changes in the refractive index in the erythrocyte cytoplasm with a change in the tonicity of the solution are observed in the nearmembrane layer. This method can find application in applied research in biology and medicine to assess the general physical properties of various cells under normal or abnormal conditions, including blood cells, bacteria, neurons, algae, cancer cells, etc.