Triple Crown of magnetic resonance

Weizmann Institute scientists are poised to race ahead in their research thanks to the arrival of a Triple Crown of magnetic resonance instruments. Lowered by enormous cranes through the roof of their buildings, these included a multi-ton, long-awaited 23.5 Tesla (T) / 1 Gigahertz (GHz) magnetic resonance instrument.

This is one of the three most powerful nuclear magnetic resonance (NMR) machines in the world, and joins another two unique heavy weights that arrived to Weizmann over the course of 2018: a 15.2T MRI scanner for preclinical imaging, and a 7T human MRI scanner for neurobiological research.

“Creating each magnet is an experiment itself. And in terms of what each one of them will allow us to explore, the sky is the limit,” says Prof. Lucio Frydman, of the Department of Chemical and Biological Physics. Prof. Frydman is a world-leading innovator of magnetic resonance. Together with Dr. Tali Scherf, Head of the Magnetic Resonance unit of the Department of Chemical Research Support, Prof. Noam Sobel from the Department of Neurobiology, and with other Weizmann scientists, he has overseen the major upgrade and expansion of the Institute’s capabilities in this realm.

First came a 15.2T scanner for preclinical research, the highest field commercial machine available for magnetic resonance imaging of rodents. Then came a 7 T MRI installed as part of the Azrieli National Institute for Human Brain Imaging and Research, the highest field machine that is clinically allowed for use in human studies (also this one had to be lowered through the roof). Finally, in December 2018, the 23.5 Tesla MR machine arrived to its new home in Rehovot.

Magnetic resonance instruments come in two basic types. NMR spectroscopy is used as a sort of molecular microscope, capable of seeing details down to atomic-level details. These machines reveal the structures and the functioning of complex biomolecular machines such as proteins doing catalysis, or protein/nucleic acid complexes like the ribosome that power living cells. Meanwhile, better-known MRIs of the kind that are used in hospitals for diagnosis, are also fundamental in science labs for a wide range of studies, from elucidating the activity of brains to understanding the behavior of cells and tissues in health and disease.

A large number of Weizmann scientists require the level of resolution and sensitivity that the 23.5T NMR, the 15.2T animal and the 7T human MRI, offer for their work. Dr. Rina Rosenzweig in the Department of Structural Biology will use advanced ultrahigh field NMR methods to understand the structure, dynamics, and interactions of large protein assemblies, such as those related to protein mis-folding and aggregation that cause neurodegenerative disorders such as Alzheimer’s disease. Dr. Michal Leskes in the Department of Materials and Interfaces plans to use its tremendous power to spy on the chemical interactions on the electrodes of batteries, in search of better solutions for powering devices from cell phones to autos.

Prof. Phillip Selenko uses the capabilities arising from the highest-field instruments to visualize the function and fate of proteins inside living cells. Dr. Amnon Bar-Shir uses high-field NMR and MRI to help create new biosensors and tracers in his molecular imaging lab at the Department of Organic Chemistry. Dr. Assaf Tal from the Department of Chemical and Biological Physics requires the highest sensitivity and resolution possible to quantify and to spatially map the metabolites driving life in the brains of animals and humans. Another recent hire at the Department of Neurobiology, Dr. Rita Schmidt, relies on high fields to connect the electrical properties of the working human brain with its physiological functions.

No small feat

Building and delivering all the magnets took somewhat of a saga – but none more challenging than that of the 23.5 T “beast”. It took three tries over more than a year to create and wind many kilometers of superconducting wire, needed to produce the core of the machine. The most demanding section of this superconducting wire had to be “baked” before testing, assembled in the final system, and tried at full field. Each time a defect was found, the manufacturer had to discard the wire and start over. Once completed the NMR instrument was flown to Israel; it took three tractor trailers to bring the magnet and the tons of ancillary sophisticated electronic and mechanical equipment that came with the magnet, into the Institute. Much of this ancillary equipment also had to “fly in” through the roof, as it would not fit through regular doors. A few weeks later, the crane returned and the roof was temporarily removed in order to set the massive instrument onto its custom-built, final legs.

Three teams of technicians from the manufacturer, Bruker, flew in to help with various stages of the installation to help assemble the array of electronic controls. Once it was assembled, the installation team working together with Institute scientists began a two-week-long process using liquid nitrogen to chill the cooling jacket that surrounds the magnetic coils and actual NMR probe. Then the inner compartment had to be super-cooled with liquid helium, a process that took a few more days. After the magnet reached operating temperatures, the team began energizing the magnet to its final field of 23.5 Tesla –also a long and stressing procedure taking several days. Once the magnet was “on-field” the group began testing the electronics, taking initial test shots, and making interactive adjustments to the magnetic field. All this was a perilous process: similar machines have known to fail several times during the powering up phase, until an eventual successful operation.

The Weizmann team hopes to have everything working by the end of April, and once stably installed, the machine should last for decades (an earlier generation 800 MHz machine installed in 1998, for instance, is still in regular use). “We have launched a renaissance in magnetic resonance research here at the Weizmann Institute. We have recruited a cadre of excellent young scientists who rely on MR for their research, and have provided them with access some of the most powerful machines of their kind in the world.” Prof. Frydman said. “Now it’s time to get out of their way, and let them win their races.”

Prof. Lucio Frydman is supported by the Adelis Foundation, the Clore Institute for High-Field Magnetic Resonance Imaging and Spectroscopy, the Comsaroff Family Trust, the Leona M. and Harry B. Helmsley Charitable Trust, the Katz Institute for Material Sciences and Magnetic Resonance Research, the Helen and Martin Kimmel Award for Innovative Investigation, the Helen and Martin Kimmel Institute for Magnetic Resonance Research, the Dr. Dvora and Haim Teitelbaum Endowment Fund, Emil and Rita Weissfeld Family Foundation, and the European Research Council. He is the incumbent of the Bertha and Isadore Gudelsky Professorial Chair.