A new tool for the observation of embryos and other large specimens: confocal theta fluorescence microscopy

Abstract

SUMMARY A theta microscope for three objective lenses was designed and built at the European Molecular Biology Laboratory (EMBL). It was used to evaluate the principles of confocal theta fluorescence microscopy and to prove its ability to handle biological specimens. A resolution improvement over confocal fluorescence microscopy has been predicted due to a detection at an angle to the illumination axis. This is verified using fluorescent beads and a fluorophore‐coated capillary. The suitability of theta microscopy for the observation of biological specimens is verified by observing a FITC‐labelled mouse embryo. In addition, the design of a theta microscope and the handling of biological material are explained in detail.