In collaboration with the National Center for Microscopy and Imaging Research (NCMIR) at the University of California San Diego, Zeiss has released a new focal charge compensation module for block face imaging with its GeminiSEM and 3View from Gatan.
Focal charge compensation expands versatility and considerably increases data quality without prolonging acquisition times and enables easy imaging of even the most charge-prone samples. Resin-embedded tissues and cells can be imaged without charging artifacts, while the pixel dwell time is reduced. Decreasing beam exposure time not only ensures fast acquisition rates, but also guards against sample damage, which is key to acquiring reliable and reproducible 3D data. Professor Mark H. Ellisman, Director of NCMIR, says “Focal Charge Compensation will breathe new life into block face scanning electron microscopy by allowing high quality imaging of previously intractable specimens, including legacy samples prepared with traditional electron microscopy stains.”
This extension of the 3View system eliminates specimen charging. A gas injection system consisting of a tiny capillary needle is precisely located above the sample. Nitrogen is guided through this needle directly onto the block face surface while the chamber is maintained under high vacuum. This eliminates charging without degrading image quality. The needle retracts automatically during the cutting cycle so the workflow is uninterrupted and high acquisition rates are maintained.
The 3View system consists of an ultramicrotome directly integrated into the vacuum chamber of the Sigma and GeminiSEM field emission scanning electron microscopes. It enables automated serial block face imaging of embedded samples (e.g. cells or tissue) with a slice thickness down to 15 nanometres. The sample is continuously cut and imaged, and a three-dimensional rendering of the sample with nanometre-scale resolution can be reconstructed.
