There is a need for a noninvasive technique to monitor living pluripotent stem cell condition without any labeling. We present an optical imaging technique that is able to capture information about optical path difference through the cell and cell adhesion properties simultaneously using a combination of quantitative phase microscopy (QPM) and interference reflection microscopy (IRM) techniques. As a novel application of QPM and IRM, this multimodal imaging technique demonstrated its ability to distinguish the undifferentiated status of human induced pluripotent stem (hiPS) cells quantitatively based on the variation of optical path difference between the nucleus and cytoplasm as well as hiPS cell-specific cell adhesion properties.

Cell membrane motions of living cells are quantitatively measured in nanometer resolution by low-coherent full-field quantitative phase microscopy. Our setup is based on a full-field phase shifting interference microscope with a very lowcoherent light source. The reflection mode configuration and the low-coherent illumination make it possible to differentiate the weak reflection light from the cell membrane from the strong reflection from the glass substrate. Two cell populations are quantitatively assessed by the power spectral density of the cell surface motion and show different trends.

Abstract— We developed a photon counting TV camera system, which uses an image guide consisting of tapered optical fibers, for the rapid detection and counting of microscopic sized luminous particles in a wide field. Using a luminous bacterium as a standard, we compared this image guide‐coupled TV camera to a lens‐coupled TV camera by determining their light collecting powers and detection abilities for single bacteria on a membrane filter. The image guide shortened the detection time by an order of magnitude, making the photon counting TV camera a practical system for rapid counting of bacteria.

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