Sample holder for axial rotation of specimens in 3D microscopy

Summary In common light microscopy, observation of samples is only possible from one perspective. However, especially for larger three‐dimensional specimens observation from different views is desirable. Therefore, we are presenting a sample holder permitting rotation of the specimen around an axis perpendicular to the light path of the microscope. Thus, images can be put into a defined multidimensional context, enabling reliable three‐dimensional reconstructions. The device can be easily adapted to a great variety of common light microscopes and is suitable for various applications in science, education and industry, where the observation of three‐dimensional specimens is essential. Fluorescence z‐projection images of copepods and ixodidae ticks at different rotation angles obtained by confocal laser scanning microscopy and light sheet fluorescence microscopy are reported as representative results. Lay In common light microscopy samples are often located on glass slides or specific dishes, and observation is only possible from one side, namely perpendicular to the slide. However, for larger three‐dimensional (3D) specimens observation from different views is desirable. Therefore, we developed a sample holder permitting rotation of the specimen perpendicular to the light path of the microscope. The specimen is placed within a glass capillary of cylindrical shape which is optically coupled to a surrounding capillary of rectangular shape fixed under the microscope. By rotating the inner tube, the specimen can thus be observed from any desired perspective perpendicular to its longitudinal axis. Using established techniques of 3D microscopy, e.g. confocal laser scanning or light sheet fluorescence microscopy, image stacks are recorded under different angles and used for reconstructing the three‐dimensional shape of the object. Fluorescence z‐projection images of copepods and ixodidae ticks at different rotation angles are reported as representative results. In addition, the device can be easily adapted to a great variety of common microscopes and is suitable for various applications in science, education and industry, where the observation of three‐dimensional specimens is essential.