Prof. M. Šimėnas Secures Prestigious European Grant to Enhance Sensitivity of Electron Paramagnetic Resonance by Thousand Times

This year, a prestigious European Research Council (ERC) grant was awarded to Prof. Mantas Šimėnas, a researcher from the Institute of Applied Electrodynamics and Telecommunications at the Faculty of Physics (FP) of Vilnius University (VU). His team will use the EUR 2.5 million Starting Grant, allocated for five years, to increase the sensitivity of electron paramagnetic resonance (EPR) spectroscopy.

According to Prof. Šimėnas, the aim of the winning project ‘Strongly Enhanced Sensitivity EPR through Bimodal Resonators and Quantum-Limited Amplifiers, Strong-ESPRESSO’ is to reduce the time required for EPR experiments by a factor of several thousand and to translate these improvements into the study of new systems: ‘EPR is a powerful tool used in a wide range of disciplines, including biology, chemistry, physics, materials science, and many others. It provides important and unique information about the material under study; however, the relatively low sensitivity of this method limits its use. For some critical materials, EPR studies can take up to a week, and, if even longer experiments are needed, we consider the system to be practically unmeasurable with EPR.’

The sensitivity has already been increased, new target – 5,000 times

In 2022, a Marie Skłodowska-Curie grant was awarded to the VU researcher, allowing the research team to improve the sensitivity of the EPR by a factor of several hundred. According to Prof. Šimėnas, the project is a natural but non-trivial extension, which is expected to shorten the time of EPR experiments by up to five thousand times.

‘Imagine that you used to spend a week measuring a protein system. Now, it would take about two minutes. This saves a huge amount of precious resources that can be used for even more research,’ says the scientist.

He asserts that the ERC funding scheme is essential for its prestige and practical benefits: ‘This generous grant is one of the most favourable in Europe. It allows the researcher and their team to stop worrying about costs and concentrate on their research. Of course, there’s a long road beforehand in terms of developing the research concept, completing the application, and, ultimately, performing well in the competition. However, the institutional support at the University motivates me,’ the interlocutor says.

Improvement can contribute to a better understanding of degenerative diseases

‘EPR is a spectroscopic research tool that allows us to study the spins of unpaired electrons. In nature, most electrons are paired, but there are some materials where the electron has no pair, i.e. its spin is not compensated. These so-called paramagnetic systems can be detected with EPR, providing beneficial, often unique information about the material under investigation – from proteins and catalysts to solid-state systems for quantum technologies,’ clarifies Prof. Šimėnas.
The researcher goes on to explain that the advantage of EPR is its selectivity. Most other methods observe the collective response of all the atoms in the material, but EPR can only focus on the atom with the unpaired electron. This selectivity allows specific protein sites to be examined and thus determine the structure of the protein.

‘Alongside other studies, we will also look at proteins involved in forming various neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Therefore, improvements in the sensitivity of EPR study methods will allow us to significantly extend these studies, including protein systems that EPR cannot currently study,’ explains Prof. Šimėnas.

The project will also study new types of catalysts and various spin platforms for future quantum technologies.

Quantum and other complex technologies

‘In this project, we intend to borrow and adapt tools from the field of quantum technologies. One of them is a quantum-limited microwave amplifier with the minimum possible noise, as quantum mechanical processes limit the noise of such amplifiers. In general, EPR studies are hampered by thermal noise, which significantly increases the duration of experiments. We want to use these sophisticated amplifiers to improve EPR’s sensitivity drastically,’ says Prof. Šimėnas.
In this project, the researcher discusses his plan to use other sophisticated tools, such as a bimodal microwave resonator.

‘In EPR studies, we want to concentrate the microwaves where the sample is located – the microwave resonator does that. Conventional EPR resonators have a single mode – they resonate at a single frequency. Bimodal resonators have two modes: they may have the same frequency, but their fields are perpendicular in space, i.e. the two resonances do not interact. If we put a system of electron spins in such a resonator, it is through the spins that interaction is created between the two modes. In this way, we can use one mode to excite the spin system and the other to read the excitation of the spins, thereby isolating the detector from the loud thermal noise that comes with the excitation signal,’ Prof. Šimėnas says.

‘Among other innovations, we will use a millikelvin dilution refrigeration system to cool resonators and amplifiers. Millikelvin is close to the lowest possible temperature – almost absolute zero, at -273.15 °C. We will buy a special dilution fridge to reach these extreme temperatures. It will be the first in the region to open up a wide range of research and development opportunities for quantum technologies in Lithuania. It is great that our funding makes it possible to stop worrying about how and where to buy the sophisticated equipment needed for the research,’ says the VU researcher.

This year, Prof Patrick Pausch, a researcher from the Life Sciences Center (LSC) at VU, also received an ERC Starting Grant in Lithuania. The only other ERC Starting Grant to have previously been awarded to a researcher in Lithuania was to Dr Stephen Knox Jones from the LSC at VU. The 2024 ERC Starting Grant competition attracted 3,500 researchers from European Union Member States and the countries associated with Horizon Europe, 494 of whom were awarded funding. The grant won by Prof. Šimėnas is the first ERC grant awarded to VU FP.