Carl Zeiss Microscopy has incorporated a Q150T coater into their rugged MinSCAN solution - designed for the mining, geosciences and oil & gas sectors.

The ZEISS mining and geosciences applications development group have chosen to use Quorum’s Q150T carbon & sputter coater to prepare mineral samples for analysis on their MinSCAN mineralogy laboratory system.

Shaun Graham is part of the applications development team at Carl Zeiss Microscopy based in Cambridge. With a Masters in applied and environmental geology, he works in the geosciences, mining and oil & gas sectors to provide analytical solutions using scanning electron microscopy performed on mineral samples. This includes the provision of sample preparation equipment including a turbo-pumped coater from Quorum Technologies

One of the main applications of the geosciences business, with its automated mineralogy software, is to provide data on mineral processing plant products from mining companies. It is vital that operating mines are able to track mineralogical and textural variation for processing and recovery optimizations. Recognising variability can save or make huge amounts of money to a company by maximizing yield and quality. The instrumentation has to be rugged and extremely reliable as it will often be located at the mine site itself. This has to be easy-to-use. Operators are not qualified scientists. They just require quick, accurate and actionable data to make informed decisions.

ZEISS supplies a special dedicated package to deliver to these requirements. This comprises sample preparation equipment and a “ruggedized” SEM. The system, known as MinSCAN, has been designed for this challenging environment, a mine-site mineralogy laboratory on wheels! A powerful data system takes the results to enable an increase in profits through greater concentrate quality and reduced losses to tailings (the materials left over after the process of separating the valuable fraction from the uneconomic fraction of an ore.). Being able to rapidly troubleshoot recovery issues, optimize plant performance and complement assays gives metallurgists, mine managers and superintendents the confidence to make effective decisions based on reliable, quantitative data. 

Key to reproducible sample preparation is a Quorum Q150T providing high resolution carbon and sputter coating. Each 30 mm standard sample requires reproducible, uniform, thin coatings. Carbon coating is used in perhaps 80% of the applications where mineral particles are being investigated. For oil and gas applications, the ability of having a thin coating becomes most important when making porosity measurements. Uniform thinness will greatly reduce imaging artefacts. As Shaun says about the selection of Quorum coaters, “the Q150 series has been chosen based on its proven extremely reliable performance in what is usually a difficult environment far removed from the traditional research bench. The coater has to be available 24/7 as the failure to be able to coat a complete batch of daily samples in a day will risk loss of profit through the lack of actionable data from that days production. This is so important to our users that ZEISS supply, install and train users on all elements of the experimental process.” 

Technical Director, Bob Morrison, says “Quorum has a long established track record as the preferred supplier of coaters for mining applications. Reliability is extremely important in these situations and we have been able to demonstrate the reliability and performance of the Q150T coater in our dealing with partners like Zeiss over a number of years.” The Q150T is available in three formats: sputtering, carbon evaporation or both. Depending upon the selected configuration, the Q150T can be a top-of-the-range sputter coater for high resolution scanning electron microscopy (SEM), a carbon coater suitable for SEM and transmission electron microscopy (TEM), or both - in a single easy-to-use system. Other options include metal evaporation and aperture cleaning.

The Jensen Laboratory at the HHMI, Caltech, incorporates the Quorum Cryo-SEM preparation system in microbial cell biology with electron cryotomography

Alasdair McDowall is the EM Center Director in the Jensen Laboratory at the Howard Hughes Medical Institute located at Caltech. Headed by Professor Grant Jensen, the Lab uses Electron Cryotomography (ECT) to study the molecular architecture of microbial cells and HIV in their native state.

The focus is on the fundamentals of microbial cell biology such as cell division, movement and secretion, as well as the structure of HIV at all stages of its lifecycle. The lab opened its doors in 2002 and continues to push the boundaries of high resolution imaging today. However, the investigation of frozen hydrated whole cells (beam and vacuum sensitive materials) in the electron microscope chamber requires new solutions. The advances in techniques for the preparation of cells by Cryo Focused Ion Beam Milling for structural characterization have recently provided a new insight of these delicate cellular architectures.

Cryo Focused Ion Beam milling (cryo FIB milling) is a cutting-edge method for thinning vitrified biological samples that allows access to intracellular regions of thick specimens (> 1 um) with unprecedented ease and structural preservation. It provides the ability to move beyond imaging only small bacterial cells with electron cryotomography (ECT) and will allow the exploration of eukaryotic cells, tissues and microbial biofilms to the same molecular resolution that the group has achieved with individual bacterial cells for the past decade. In addition, the ability to thin individual bacterial cells before imaging, without perturbing their structure, will provide higher contrast and resolution when necessary, even within already thin bacterial cells. Furthermore, the addition of a cryo-stage to the existing FIB mill at Caltech will allow for further development of much needed methods for correlating fluorescence microscopy and electron tomography for the targeting and identification of specific structures deep within eukaryotic cells, bacteria and tissues.

Dr McDowall uses the Quorum PP3010T cryo sample preparation system. This is a highly automated, easy-to-use, column-mounted, gas-cooled Cryo-SEM preparation system suitable for most makes and models of SEM, FE-SEM and FIB/SEM. The Jensen group uses their prep system with an FEI Versa scanning electron microscope. Dr McDowall says “The Quorum PP3010T is ideal for our vitreous cell transfers when dedicated to maintaining the cryogenic amorphous state during SEM and DualBeam specimen preparation. The PP3010T allows easier and more practical operation for milling cryo preserved specimens for electron tomography. Its design assists the investigation of frozen hydrated cells and tissues by providing a mechanism for hydrated sample transfer, cryogenic cooling and temperature control within the SEM or Small Dual Beam during the milling process. In our operation, the Quorum PP3010T was added to an existing FEI Versa Dual Beam Scanning Electron Microscope in a climate controlled room courtesy of the Greer group, California Institute of Technology.”

Experienced electron microscopist, David McCarthy, talks about working with Quorum and his use of their coaters and cryo-SEM preparation instrumentation.

David McCarthy has been working in the world of electron microscopy since the early 70s. In this time, he has seen many changes in instrumentation, techniques and sample preparation methods.

His career started back at the London Hospital Medical School for four and a half years before a move that would see him start and manage the Electron Microscopy Unit at the School of Pharmacy, University College London for thirty eight years. In this time, he has used a number of EMs starting with Philips and JEOL systems. In 1991 he was able to purchase the first fully digital SEM in the UK, a Philips XL20. Then on to larger chamber XL30 and in 2009 he ended up with the FEI Quanta 200 FEG. This gave him a versatile, high resolution low-vacuum FEG SEM to handle really challenging thermally and vacuum sensitive samples and dynamic experiments. In parallel with the microscopes came new and more advanced accessories enabling advanced cryo-imaging. At all times, a high performance vacuum coating system was essential to McCarthy’s work.

McCarthy has worked with Quorum over many years. For example, while running the EM Unit at UCL, he acquired a PP3010T cryo-SEM preparation system, a highly automated, column-mounted, gas-cooled sample preparation and transfer system. He also used their Q150T series of sputter and carbon coaters, something he has continued to this day with his contract service business based out in rural Suffolk. DM Microscopy offers McCarthy’s extensive experience in electron microscopy to a range of academic and industrial pharmaceutical organisations. His new laboratory uses a Tescan Vega 3 SEM, a reliable high vacuum, turbo-pumped tungsten system. It is used to enable DM Microscopy to provide rapid turnaround imaging services, vital in the world of pharma. His sample coater started life as a Q150 E compact rotary-pumped unit for evaporation applications using carbon coating of specimens. Quorum has recently upgraded the unit to a Q150R ES to provide gold sputtering of samples. McCarthy is particularly impressed with his dealings with Quorum. “They provide excellent service and support on the back of a very versatile coating system. I chose the option of the quartz oscillator film thickness monitor (FTM) as this enables me to lay down very accurate amounts of material, to ensure reproducible sample preparation conditions prior to imaging. Operation is very straightforward via a touch screen. This enables me to store my protocols for ease of setting up and running.”

The Agricultural Research Service of the USDA uses a Quorum Cryo-SEM preparation system for the study of mites, ticks and other soft bodied organisms

Dr Gary Bauchan is the Director of the Electron and Confocal Microscopy Unit at the Agricultural Research Service (ARS), the principal in-house research agency of the United States Department of Agriculture. The Unit is a core facility with the responsibility of providing collaborative assistance to scientists from ARS, Northeast Area and Beltsville Agricultural Research Center (BARC) who have microscopy applications that require high resolution imaging. Dr Bauchan’s team have produced images using electron microscopes of bacteria, fungi, mites, insects, nematodes and parasites along with plant and animal tissues both healthy and diseased. One of his major collaborations is with Dr Ron Ochoa, the world’s expert on plant feeding mites.

Biological specimens require special treatment due to the high water content of the samples. Many of the specimens are in liquid cultures or are very soft-bodied and by using classical preparative techniques will either destroy the specimen or distort the specimen producing artefacts. A cryo-prep system is an ultra-fast method to ready the specimens for observation in a SEM especially a high resolution field emission SEM. Thus, specimens are frozen in time to allow for observation of feeding behaviour, mating behaviour, host/parasite interactions, etc. It preserves the natural orientation of ultrafine structures such as setae, antenna, legs, skin texture, sensory organs, waxy coatings and eggs.

Asked about his experience using a Quorum PP2000 Cryo-SEM preparation system on the Hitachi S-4700 field emission scanning electron microscope, Dr Bauchan said “The Quorum system is easy to use, the set-up for imaging is logical, durable, reliable, and maintains ultra-low temperatures for a long period of time. Holders containing pre-frozen samples are transferred into the cryo-prep chamber where they are etched to remove any surface contamination (condensed water vapour) by raising the temperature of the stage from -130 ºC to -90 °C for 10-15 minutes. Following etching, the temperature inside the chamber was lowered below -130 °C, and the specimens were coated with a 10 nm layer of platinum using a magnetron sputter head equipped with a platinum target. The specimens were transferred to a pre-cooled (-130 °C) cryo-stage in the SEM for observation.”

The system has been used in multiple projects by the Unit, many of which have been published with the generation of stunning, colourful images. The use of low temperature SEM has been shown time and again to be the best method for the examination of microscopic biological specimens and their ultrastructure. The work in conjunction with Dr Ochoa has been particularly productive with five papers published this year to date. These have focused on the field of acarology, a branch of zoology dealing with the study of mites and ticks.


Above image: Gary Bauchan, Director, Electron & Confocal Microscopy Unit, USDA-ARS inserts mite specimens into the Quorum PP2000 Cryo-Prep Chamber (photo courtesy of Steve Ausmus, USDA-ARS, d3713-1)

Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA.


The Biomedical Imaging Unit at the University of Southampton uses Quorum coating system as a general purpose work station

The Biomedical Imaging Unit (BIU) is a core facility, which provides a diagnostic and research service in high quality/high resolution microscopy. It is a joint facility run for the benefit of, and jointly funded by, the University of Southampton and Southampton University Hospitals NHS Trust with eight full time staff.

The microscopes in the Biomedical Imaging Unit are used extensively for research, teaching and diagnostic work by staff and students across the Trust and University with some 100-150 users per year from most science faculties including Medicine, Physics, National Oceanographic Centre, Engineering and Biological Sciences. This nationally important unit is extremely well equipped with two new microscopes to enable it to do 3D microscopy in addition to the existing transmission and scanning electron microscopes, confocal and time lapse light microscopes, image analysis and video microscopes.

The Quorum Q150T ES coater was purchased to replace a very old (1960s vintage) Edwards coating unit. It is being used as a general purpose workstation for carbon coating, sputter coating for high resolution SEM, glow discharging grids, cleaning apertures etc.

Discussing the purchase, Anton Page, Head of the BIU, says, “We looked at various competitive systems but these did not fit our needs nor matched our price constraints. The new coater is ideal. It is a combined system providing both sputtering and carbon coating. The deposition heads can be swapped in seconds and the intelligent system logic automatically recognises which head is in place and displays the appropriate operating settings.”

“Furthermore, for us, it is very fast! Our old coating unit took half a day (really!) to pump down before we could use it. The Q150T ES is a turbo pump system and can do the same job in 10 – 15 mins and get a better result. Newer coating units are obviously also much quicker than our old one but this is much more versatile – it has interchangeable head inserts – one for carbon coating and one for sputter coating which prevents cross-contamination of specimens, making cleaning easier too. It is simple to use and so we can teach our users how to coat their specimens instead of doing it for them.”

The Quorum Q150T ES is one of a family of coaters designed for applications across the spectrum of electron microscopy. Thousands of Q150 and Q300 coaters are used in EM laboratories around the world - and increasingly for many thin film coating applications.


Patricia Goggin from the University of Southampton working with the Quorum Q150T ES coating system (l). A transmission electron micrograph of immuno-gold labelled amyloid beta fibrils (r) prepared by Savannah Lynn

The Institut Charles Sadron at the CNRS-University of Strasbourg uses the Quorum Cryo-SEM preparation system for research in polymers and self-assembled systems

The Quorum PP3010T's ability to provide stable temperature regulation of samples ensures the facility gets the highest resolution when imaging delicate materials.

The Institute Charles Sadron is a CNRS-Institute located at the University of Strasbourg and performs fundamental and applied research on polymers and self-assembled systems. Dr Marc Schmutz works in the Electron Microscopy facility where he uses a Hitachi SU8010 Ultra High Resolution Field Emission Scanning Electron Microscope in conjunction with a PP3010T Cryo-SEM preparation system from Quorum Technologies. It is used to study a broad variety of materials from crystalline polymers to dragonfly wings. It is vital to be able to observe samples in, as close as possible to, their native state, either hydrated or in organic solvents.

Describing his choice of cryo-preparation system, Dr Schmutz says, “We picked the Quorum system because of its stable temperature regulation; each part of the system is independently controlled (cold stages and cryo-shields). This makes sure we will get the highest resolution when imaging our delicate materials.”

Examples of this work are shown in a recently published paper in the ACS Journal of Physical Chemistry where the drying mechanisms in plasticised latex films are studied with respect to their horizontal drying fronts. The drying kinetics of latexes with particles made progressively softer by adding increasing amounts of a plasticiser, in relation to speeds of horizontal drying fronts and particle deformation mechanisms are reported. [1] To examine the extent of particle deformation inside the dry films, a special sample holder was designed and built, allowing us to take cryo-SEM images of a cross section. Samples of the film were cut out with a razor blade, then fixed in the holder and rapidly plunged into liquid nitrogen slush (in the Quorum PP3010T PrepDek). After introduction into the preparation chamber, the films were then freeze-fractured at −150 °C with a cooled scalpel blade under high vacuum and coated with a thin layer of platinum. They were subsequently imaged in the SEM. 

The PP3010T is a highly automated, easy-to-use, column-mounted, gas-cooled Cryo-SEM preparation system suitable for most makes and models of SEM, FE-SEM and FIB/SEM. 



Left: Quorum PP3010T Cryo preparation system (left) mounted on Hitachi SU8010 FE-SEM at ICS-CNRS-unistra.

(Above: Latex film at high water content vitrified with the Quorum PT3010T. Small arrows point to the latex beads and the longer ones to the water area. (unpublished work))




Reference

1   Drying Mechanisms in Plasticized Latex Films: Role of Horizontal Drying Fronts, V. Divry, A. Gromer, M. Nassar, C. Lambour, D. Collin, and Y. Holl, J. Phys. Chem. B, 2016, 120 (27), pp 6791–6802. DOI: 10.1021/acs.jpcb.6b03009

The Sainsbury Laboratory at the University of Cambridge uses Quorum Cryo-SEM preparation system for research in plant biology

The Sainsbury Laboratory Cambridge University (SLCU) is a new research institute funded by the Gatsby Foundation. The aim of the Laboratory is to elucidate the regulatory systems underlying plant growth and development.

The Laboratory hosts a state-of-the-art advanced imaging facility for scientists working on several aspects of plant developmental biology, including live imaging of developing plant tissues, and high-resolution scanning electron microscopy.The facility currently has four major instruments, two stereo-fluorescence microscopes and several dissecting microscopes. 

Dr Raymond Wightman is its Microscopy Core Facility Manager. Studying plants using scanning electron microscopy (SEM) was a challenge. Prior to having a Quorum PP3010T Cryo-SEM preparation system, the lab would look at fresh plant samples that dried up and were hard to maintain while doing SEM. There was an urgent requirement for something to enable better imaging of fully hydrated plant tissue.

Asked about his experience using the Quorum PP3010T Cryo-SEM preparation system on the Zeiss EVO HD cryoSEM, Dr Wightman said “We have been impressed with the low maintenance costs and excellent applications support from the Quorum team. The system is now an integral part of the microscopy facility at the Sainsbury lab and because of the superior results we are getting now compared to before, the SEM use has gone up from about 8 hours per month to 64 hours per month. We are also able to process samples that we could not easily do prior to getting the Quorum kit.”

The system has been used in multiple projects by the Laboratory. These have included looking at the following: wood ultrastructure and cellulose organisation; observing cellular membranes; making new biocomposites and studying their properties; studying the interactions between a plant pathogen and the plant cell; studying cuticular wax formation; determining how plant cells coordinate their growth across tissues e.g. leaves and flowers. A final project on the development and structure of leaves from alpine plants where 90% of the work was performed on the PP3010T will be published shortly. All of these serve to illustrate the versatility of the Quorum cryo-SEM preparation system.





Dr Ray Wightman loads a biological sample via the Quorum PP3010T Cryo-SEM preparation system mounted on a Zeiss EVO HD cryoSEM. The image above shows yellow broccoli, cryo-prepared and platinum coated (5nm coating). Individual cells are clearly shown. (122x magnification).


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



GloQube update

We are delighted to announce that the first production batch of GloQubes has been dispatched to customers.

The GloQube is a compact, fully automated glow discharge system used for the hydrophilisation (wetting) of TEM grid support films and other applications include the modification of surfaces, for example, for the enhancement of polymer bonding.

In addition to the wetting of TEM grids, the GloQube vapour chamber is designed for hydrophilic/hydrophobic (negative or positive) conversions, typically using reagents such as methanol and alkylamine. 

Pictured is our hard working production and final test team, from left to right: Richard, Darren, Adam, Steve and Pete.

For further information and product brochure download visit: GloQube product pages.