Observation of iPS Cells by a Novel Annulus Illumination Method that Applies Light Intensity Modulation by Refraction

Abstract

We proposed a microscopy method for observing phase objects without halos or directional shadows. The key optical element is an annular aperture at the front focal plane of a condenser with a larger diameter than one used in standard phase contrast microscopy. The light flux passing through the annular aperture is changed by the specimen’s surface profile, and then it passes through an objective and contributes to image formation. Images of colonies, formed by induced pluripotent stem (iPS) cells using this method, are compared with the conventional phase contrast method. Our method obtains phase images of iPS cell colonies with clear outlines and their three-dimensional nature