Interference microscopy in cell biophysics. 1. Principles and methodological aspects of coherent phase microscopy.

The purpose of our tandem publications is to review the applications of the coherent phase microscopy to cell biophysics. In this article, we briefly consider the fundamentals and methodological aspects of the coherent phase microscopy (CPM). One of important advantages of this method is a high sensitivity of CPM images to changes in physical-chemical properties of biological samples. The optical path length difference (OPLD), measured with CPM instruments in different domains of an object, serves as the informative optical parameter used for visualization of individual cells or intracellular organelles. Metabolically dependent variations of CPM images reflect changes in the functional state of biological objects. In the next article, we review results of CPM studies of different cells and intracellular energy-transducing organelles.