Zeiss GeminiSEM 460 with Volutome

Electron Microscopy Unit (EMBI) is acquiring an automated serial block face scanning electron microscope (SBF-SEM) suitable especially for large volumes and broad variety of specimen types. The new system will replace the aged system, which has been the most used instrument of the unit, used in numerous high-profile projects and attracted several international projects. Moreover, due to fast developments in the field, new instruments have higher sensitivity and provide better resolution than earlier systems, allowing imaging of new types of samples. EMBI is a multi-user environment and, thus, the two main criteria for selection of the instrument are (1) image quality and (2) suitability for wide range of different tissue and cell types with different size and imaging requirements.

(1) After thorough testing of the available systems using similarly prepared tissue and cell monolayer samples and systematic comparison of the results, Zeiss GeminiSEM 460 with Volutome was found to provide superior imaging quality on both test samples in terms of signal-to-noise in both low and high vacuum modes and higher sharpness especially on long runs of the tissue sample. Charging (electron beam interacts with the nonconductive resin in which the sample is embedded) is one of the main limiting factors in SBF-SEM imaging, and the superior image quality in the test runs is due to focal charge compensation system (FCC), which is a patented solution of Zeiss. FCC proved to be superior in reducing charging artefacts while still providing better signal-to-noise ratio in our samples in comparison to low vacuum mode imaging, which is the only solution provided by other vendors to reduce charging. Zeiss Volutome is also the only system that has a dedicated automated retractable detector for SBF-SEM imaging operating both at high and low vacuum modes, which enables uninterrupted imaging during runs requiring switching between high and low vacuum modes on non-uniform samples. (2) Zeiss GeminiSEM 460 with Volutome has unique features to address various sample-specific needs that are often encountered in EMBI: - 32k x 24 k image size with 16-bit mode, which provides flexibility over 8-bit mode to correct image contrast during post-processing in situations when imaging conditions are changing. At the same time, contrast and brightness adjustments do not have to be very precise during the run providing more flexibility for the experiment design. This factor is important especially in larger samples that may have staining intensity gradient. - oscillating knife, which improves sectioning of challenging samples, such as soft (as a consequence of poor polymerization due to high humidity in summer) or non-homogeneous blocks (comprising of dense and loose tissue with lots of empty resin in-between). - sample hight of 1 mm (in extreme situations up to 1.2 mm), which allows imaging of large or long tissue samples such as plant roots and brain pieces. There’s no other supplier in the market that can deliver a SBF-SEM system with the required image quality due to focal charge compensation system (FCC) and 32k x 24 k image size with 16-bit mode which are features that can be only found in Zeiss GeminiSEM 460 with Volutome.