New method combines zero to ultra-low field NMR with special hyperpolarization technology to detect alcohols

New method combines zero to ultra-low field NMR with special hyperpolarization technology to detect alcohols

Nuclear magnetic resonance (NMR) is an analytical tool with a wide range of applications, including magnetic resonance imaging, which is used for diagnostic purposes in medicine. However, NMR often requires the generation of strong magnetic fields, which limits the scope of its use. Researchers at Johannes Gutenberg University Mainz (JGU) and the Helmholtz Institute Mainz (HIM) have now discovered new ways to reduce the size of corresponding devices and also the possible associated risk by eliminating strong magnetic fields. This is achieved by combining so-called zero to ultra-low field NMR with a special hyperpolarization technique. "This exciting new method is based on an innovative concept. It opens up a whole range of possibilities and overcomes previous disadvantages," says Dr. Danila Barskiy, Sofja Kovalevskaja Prize winner, who has been working in the relevant discipline at JGU and HIM since 2020.

New approach to enable measurements without strong magnetic fields

The current generation of NMR devices is extremely heavy and expensive - because of the magnets. Another complicating factor is the current shortage of liquid helium, which is used as a coolant. “With our new technique, we are gradually moving ZULF NMR towards a completely magnet-free state, but we still have many challenges to overcome,” said Barskiy.

In order to make magnets superfluous in this context, Barskiy came up with the idea of ​​combining zero to ultra-low field nuclear magnetic resonance (ZULF-NMR) with a special technique that makes it possible to hyperpolarize atomic nuclei. ZULF NMR is itself a recently developed form of spectroscopy that provides rich analytical results without the need for large magnetic fields. Another advantage over high-field NMR is the fact that its signals can be easily detected even in the presence of conductive materials such as metals. The sensors used for ZULF-NMR, typically optically pumped magnetometers, are highly sensitive, easy to handle and already commercially available. Thus, it is relatively easy to assemble a ZULF NMR spectrometer.

SABER Relay: Transmit rotation command like a baton

However, the NMR signal produced is an issue that needs to be addressed. The methods used to generate the signal so far are only suitable for analyzing a limited selection of chemicals or are otherwise associated with exorbitant costs. For this reason, Barskiy decided to use the SABER hyperpolarization technique, which allows large numbers of nuclear spins to be aligned in solution. There are a number of such techniques that would produce a signal sufficient for detection under ZULF conditions. SABER, short for Signal Amplification by Reversible Exchange, has proven to be particularly suitable. At the heart of the SABER technique is an iridium metal complex that mediates the transfer of the spin order of parahydrogen to a substrate. Barskiy has managed to circumvent the disadvantages of temporarily binding the sample to the complex by using SABER-Relay, a very recent improvement to the SABER technique. In this case, SABER is used to induce polarization, which is then passed on to a secondary substrate.

Spin chemistry at the interface of physics and chemistry

In their paper entitled “Relayed Hyperpolarization for Zero-Field Nuclear Magnetic Resonance” published in Science Advances, Drs. Danila Barskiy, lead author Erik Van Dyke and their co-authors, how they were able to detect the signals for methanol and ethanol extracted from a sample of vodka. “This simple example shows how we were able to expand the scope of ZULF NMR using a cost-effective, fast and versatile method of hyperpolarization,” summarizes Barskiy. “We hope we have moved closer to our goal of enabling the development of compact, portable devices for analyzing fluids such as blood and urine and, in the future, potentially enabling discrimination of certain chemicals such as glucose and amino acids.”

Danila Barskiy received a Sofja Kovalevskaja Prize from the Alexander von Humboldt Foundation in 2020 and subsequently moved from the University of California, Berkeley to Mainz, where he began researching in the group of Professor Dmitry Budker at the Institute of Physics and HIM at JGU. Barskiy works in the field of physical chemistry and leads a research group exploring the potential applications of NMR in chemistry, biology and medicine.

Source:

Johannes Gutenberg University Mainz

Reference:

Van Dyke, ET, et al. (2022) Relayed Hyperpolarization for Zero-Field Nuclear Magnetic Resonance. Scientific advances. doi.org/10.1126/sciadv.abp9242.

.