Posts from July 2016

The College of New Jersey use the Quorum Cryo-SEM preparation system in a project to study ice crystals in high altitude clouds

A Quorum PP3010T is helping to advance the understanding of the physical role of ice crystals.

Dr Nate Magee is an associate Professor of Physics at The College of New Jersey (TCNJ) where he leads a team working to advance the understanding of the physical role of ice crystals in processes with high altitude clouds.  Cirrus clouds are primarily composed of ice crystals that interact with solar radiation and IR radiation from the ground, and they play a significant, but still poorly understood role in Earth's climate.  The precise shapes and textures of these cirrus ice crystals largely determine how solar radiation interacts with the clouds (i.e. reflection & scattering angles) but the microscale structure is still fairly uncertain.  Dr Magee is working with the Quorum PP3010T cryo preparation system to make high-resolution images, 3D reconstructions and statistical measurements of ice crystals that are grown in the lab under cirrus conditions as well as ice crystals that are collected and recovered directly from high altitude cirrus using weather balloons and robotic cryo-capture.

A cryo preparation system is vital to the success of these studies. Describing the work, Dr Magee says, “Keeping ice crystals very cold (sub -150 C) means that their vapour pressure will be sufficiently low that their shape and surface structure can be "locked" in place as we image and analyse the ice particles.  Working at Peltier cooling stage temps (maybe to -50 C) would not make this possible.  The Quorum PP3010T transfer and interlock setup on our Hitachi SEM (with a few custom modifications on our part) has made it possible to transfer crystals from our lab systems directly into the SEM for imaging without exposing them to warmth or excess water vapour.”

So why did Dr Magee select the Quorum cryo-preparation package? “I have used Peltier cooling stages with FEI SEMs, which actually do have a few advantages for some types of in-situ ice growth experiments.  However, as I have said, we required sub -150 C temperatures for this study so, after considering what was available, we chose to work with Quorum.  Their full cryo temperature range and interlock prep chamber works very well for transfer experiments.  We are still working to develop its functionality for in-situ dynamic experiments on growing ice.”

This work is being presented in July at the International Conference on Clouds and Precipitation in Manchester.1,2

References

1 Magee, N.B., K. Boaggio, L. Bancroft, M. Bandamede, and K. Hurler, 2016:  Cryo-Scanning Electron Microscopy of Captured Cirrus Ice Particles.  Abstract #565, 17th International Conf. on Clouds and Precip. Manchester, UK, July 2016. 


2 Bancroft, L., K. Boaggio, K. Hurler, M. Bandamede, and N.B. Magee, 2016:  Comparative analysis of lab-grown ice crystals by Cryo-Scanning Electron Microscopy.  Abstract #566, 17th International Conf. on Clouds and Precip. Manchester, UK, July 2016.




Diamond Light Source use Quorum Cryo-SEM preparation system in conjunction with a new beamline

Diamond Light Source use a PP3000T cryo preparation system to help align protein crystals prior to X-ray macromolecular crystallography experiments.

Dr Anna Warren is a Senior Support Scientist on VMXm, a new beamline currently under development and construction at Diamond Light Source where it will be used to carry out X-ray macromolecular crystallography experiments.  Diamond offers 26 separate beamlines to aid with research groups in the UK and abroad, allowing them to determine the three dimensional structure of matter, such as protein molecules, on the atomic scale.  This can help to aid with drug design and to assist in the understanding of how these proteins function.  There are several beamlines already running at Diamond which allow the study of protein crystals ranging from 5-100 microns in size. However, as the systems get more complicated, inherently the crystals get smaller, so the beamline currently being built will allow the study of crystals ~500 nm to 5 microns in size. 

Due to the small size of these crystalsDr Warren is using a JEOL SEM to visualise the crystals and align them to the X-ray beam to carry out the experiments. The crystals are very fragile and prone to dehydration. This means they have to be stored, handled and studied at liquid nitrogen temperatures. This is where the Quorum PP3000T cryo-SEM preparation system has been of great useDr Warren takes up the story: “It has allowed us to visualise crystals less than a micron in size at cryogenic temperatures. This technique has never been used in our field in this way so we are currently carrying out a lot of research to understand the best ways of handling and preparing samples to obtain the best quality images. This would be impossible without having the Quorum preparation system and cryo-stage as the crystals would deteriorate in quality. Quorum was very helpful when we started looking at systems to purchase, especially as they have an SEM and cryo-SEM set up in Laughton. We were able to test out our samples in advance to get an understanding of whether it would work for us. Since making our purchase decision, we found that the preparation desk/slushing station have become a vital part of our sample preparation and this has been invaluable for our experiments.  

The image above illustrates the data quality we get routinely – crystals of cytoplasmic polyhedrosis virus (CPV20). The crystals shown here are in the size range 2.5 to 5 µm. 



The Quorum PP3000T cryo-SEM prep system mounted on a JEOL SEM at the Diamond Light Source