Ultra-stable liquid-nitrogen-free holder for high-resolution cryo-electron microscopy - Phase I

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One important technical problem in cryo-EM, when trying to attain atomically resolved 3D structures of frozen hydrated specimens, is the negative effect on the resolution due to vibrations and sample drift. Cryo-EM holders have so far relied on the application of a dewar that has to be filled with LN to cool down the specimen to temperatures below -145 C. However, the use of LN is often inconvenient. Water crystallization inside the dewar and relatively hot spots may induce vibration through LN bubbling, limiting the attainable spatial resolution. Significant user expertise is often required to circumvent these issues and perform single particle cryo-EM measurements with atomic spatial resolution, i.e. < 0.3 nm. In addition, LN spills limit the attainable single tilt angle required to recover 3D information in cryo-electron tomography studies.Waterloo researchers have designed a cryo-EM holder that does not require the use of LN, and therefore avoids the constant refilling step inherent with this method and all aforementioned issues associated with the use of LN. The design is capable of providing equal or lower sample temperatures than the current state of the art, with the additional benefit of minimal to no vibrations, no sample drift caused by LN evaporation, extended (basically unlimited) cooling periods, and any arbitrary single axis tilting.This technology has been assigned to the University of Waterloo (Waterloo) through its Commercialization Office (WatCo), which filed a US provisional patent (Petruk and Sciaini; USPTO 62/801,327, February 5th, 2019). The proposed cryogenic approach has the potential to become the method of choice in the performance of high-resolution cryo-EM work without the need of expensive cryo-TEMs with autoloaders.