Spinning Disc Enables Confocal-Like Imaging

A new disk-scanning unit (DSU) delivers confocal-like images with excellent contrast and resolution compared to conventional wide-field microscopy.

The new Olympus (Hamburg, Germany) DSU removes out-of-focus light from above and below the focal plane, particularly in specimens > 20 µm thick. To reject the out-of-focus light, the DSU places a spinning disk, with an alternating pattern of vertical and horizontal slits, in the confocal plane of the microscope. Spinning at 3,000 rpm, the slit disk creates virtual pinholes that produce a similar effect to the pinholes used in confocal laser scanning microscopy (cLSM).

DSU slit disks are designed to improve resolution, contrast, and signal-to-noise ratio in conventional wide-field fluorescence microscopy, to provide the semi-confocal optical sectioning. By using arc-lamp excitation sources, the Olympus DSU offers the wavelength flexibility within an economical package. The DSU disk and optical components are all ultra-violet (UV)-compatible, making the unit suitable for most available fluorochromes.

The crisp, confocal-like images with controllable depth of field produced by the DSU can also be collected as a series of optical sections (Z-stack) from specimens. Images are acquired using a charge-coupled device (CCD) camera, rather than the photomultiplier tubes used for cLSM, meaning that no sophisticated processing is required. By offering full-frame CCD image capture at up to15 frames/second, the DSU is an excellent tool for live-cell applications where speed of acquisition and minimal phototoxicity are required.

Disk operation is fully motorized, allowing a computer to switch remotely between wide-field and DSU modes. The system can be equipped with a motorized filter-wheel to maintain color temperature in different observation modes and includes a motorized filter turret for the convenient switching of fluorescence filter in DSU mode. In addition, the DSU is highly flexible and can be combined with motorized microscopes such as the upright Olympus BX61 and the inverted Olympus IX81 for three-dimensional (3D) semi-confocal imaging.

When integrated into versatile Olympus imaging systems, the DSU is suitable for optical sectioning in combination with a variety of dedicated imaging applications.



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