The Nuclear Magnetic Resonance (NMR) laboratory of the University of Barcelona (UB) is in luck. Because? Because yesterday he presented a unique infrastructure throughout Europe. It is a very high-field NMR spectrometer that uses high-temperature superconductors (the main novelty) and is capable of creating a magnetic field 500,000 times more intense than that of the Earth. This technology is applied in research areas such as chemistry, biology and biomedicine and is decisive for studying the characteristics of molecules and, as a result, detecting interactions between drugs and receptors, identifying new therapeutic targets and designing drugs to combat diseases.
What makes the NMR technique particular is that, unlike other technologies such as infrared, it requires a very intense magnetic field. “If you, for example, want to determine the structure of aspirin and you don’t have a magnetic field, you can’t do it,” explains Dr. Francisco Cárdenas, head of the NMR unit of the CCiTUB (Centres Científics i Tecnològics de la UB) to La Vanguardia. ), which hosts the new infrastructure. The magnetic properties of atoms are only detected in the presence of a magnetic field, it is an essential requirement.
But it is not easy to obtain such powerful magnetic fields. “We are building more and more magnets with larger magnetic fields,” says Cárdenas. For example, a button: the magnetic field of the new device (of 23.5 Teslas) is 500,000 times more intense than the terrestrial magnetic field. “Because the MRI technique is so insensitive, the larger and more powerful the magnet, the better. For this reason, since the 70s, we have gone from magnetic fields of 4 Teslas, to fields of 8, 15, 18, 20 and even 23.5. And thanks to that, sensitivity is now not so much a problem”, adds this researcher.
What had not been able to be solved, at least until now, was the fact that the most advanced material could not exceed 18 Teslas, and scientists demanded larger magnetic fields. Now, thanks to a Spanish patent -which is behind the coil material that incorporates this new equipment developed in a European project led by the Institute of Materials Science (CSIC) of Barcelona- this pioneering device has been created in Europe and second in the world -after Japan- to use high-temperature superconductors to generate magnetic fields in a 1 GHz NMR instrument.
Under certain conditions, these superconducting coils are capable of offering no resistance to the passage of electrical current (zero resistance), and allow permanent circulation of an electrical flow once it has been disconnected from the electrical network.
Until the appearance of this equipment, to achieve the superconductivity necessary to reach 18 Teslas, a superconductor at a temperature of 2 kelvins (-271.15 ?) was needed. The new apparatus works at 4 kelvin (-269.15 ?). “Going from 2 to 4 involves a very significant technological complication,” says Cárdenas. And that is precisely the novelty, that this new material with which the coil of the equipment has been made achieves superconductivity at 4 kelvins.
“So, by cooling liquid helium to that temperature [due to the extremely low transition temperatures of technically used superconductors, they need to be cooled with liquid helium, the coldest liquid on Earth], you get a magnetic field much greater than the existing one up to now and you save the technology of cooling the gas even more. It must be taken into account that this gas is very expensive and increasingly scarce. With this system, the cost of liquid helium is much smaller”.
All the magnets that were up to now – in Florence a 1.2 GHz one was installed; in Lyon one of 1 GHz- worked at 2 kelvin. This new contraption operates at 4 kelvin. “This is technological success,” underscores Cárdenas. “Before, these powerful magnetic fields were already achieved, but at an enormous cost in helium and the pumping technology to cool it, which is expensive, dangerous and complex. Now it has been simplified thanks to this high-temperature superconductor, which goes from 2 to 4 kelvins. In other words, they can work at 4 kelvins and withstand very intense magnetic fields, more than the previous generation of equipment”.
With such high magnetic fields, not only is a significant gain in resolution and sensitivity achieved, but also a significant reduction in the time to obtain data: an experiment that required a week in 800 MHz equipment can now be resolved in one day with the new gadget.
The NMR technique has multiple applications. Among them, it has the ability to indirectly measure the three-dimensional structure of something as complex as a protein. But not only that, it simplifies its spectrum. For example, in a protein like insulin, there are between 3,000 and 4,000 hydrogen, 2,000 carbon, and 500 nitrogen atoms. “It is a very crowded and overlapping spectrum,” Cárdenas argues. A magnetic field as intense as the one that this new equipment is capable of generating -which has a cost of 8.9 million euros financed thanks to a grant from the Ministry of Science and Innovation and NextGeneration funds-, not only means gaining sensitivity , but it also increases the dispersion, that is, it stretches and simplifies the spectrum.
And what does this simplification mean? “If you have the initial photo of the protein and you add a drug to it, you can see which region of it is affected by the drug. The changes in the structure with respect to the original give you an idea of ??whether there is an interaction with the drug and whether it may have a therapeutic function in the future or not. If you add the drug and the protein stays the same, it means the drug doesn’t work.”
This capacity, however, for the analysis of a protein -Cárdenas reiterates- was already available with previous devices. “What makes the new equipment very special is the ability to work at 4 kelvins,” he insists.
Another element that makes this infrastructure special is the helium reliquefaction system (also acquired by the UB), which allows the gas to be liquefied again, thus drastically reducing the consumption of such a limited resource, a system that is manufactured under Spanish license from the CSIC-University of Zaragoza.
This pioneering equipment in Europe was presented yesterday in the Barcelona Science Park of the UB (where the CCiTUBs are located) and was attended by the Minister of Science and Innovation, Diana Morant, and the Minister of Research and Universities, Joaquim Nadal .
