The Laboratory of Photochemical Radical Reactions focuses on two primary research areas: (i) the mechanisms, structure, reactivity, and dynamics of short-lived radical species in biologically relevant molecules, and (ii) the development of methods for generating and applying nuclear spin hyperpolarization. This research utilizes high-resolution nuclear magnetic resonance (NMR) techniques, coupled with electromagnetic or chemical initiation. This approach allows for the analysis of molecular reactivity, spin dynamics, hyperpolarization, and nuclear magnetic relaxation processes with microsecond temporal and atomic spatial resolution.
The Laboratory of Photochemical Radical Reactions, in collaboration with the Laboratory of Theoretical Spin Chemistry (LTSС), conducts research on spin dynamics and the mechanisms of nuclear spin hyperpolarization generation. The primary focus is on the development of efficient pulse sequences and the optimization of external conditions—such as magnetic field, resonance radiofrequency pulse frequencies and amplitudes, etc.—to create and preserve hyperpolarization in long-lived spin states.
The main methods for generating hyperpolarization are chemically induced dynamic nuclear polarization (CIDNP) and parahydrogen-induced polarization (PHIP, ODIP, SABRE), which significantly enhance the sensitivity of NMR spectroscopy and magnetic resonance imaging (MRI).
For this research, a specialized setup was established in the laboratory in 2016, based on a commercial NMR spectrometer. It enables experiments in an ultra-wide range of magnetic fields—from 10 nT (ultra-weak fields) to 9.4 T. The setup allows for rapid switching of the external magnetic field acting on the sample while maintaining high spectral resolution of the NMR spectra. This provides the ability to control the parameters of spin dynamics that are critical for efficient hyperpolarization transfer.
The measurement of nuclear spin relaxation times allows for a quantitative assessment of the stability and longevity of hyperpolarization and enables the optimization of experimental conditions for different substrates.
Furthermore, this development has made it possible to evaluate the efficiency of new contrast agents for MRI, which is an important step toward creating a new generation of biocompatible contrast and therapeutic agents. The results obtained allow for the development of compounds with targeted action in a state of enhanced MRI sensitivity, paving the way for safer and more accessible medical diagnostics.
The second research direction is dedicated to studying the mechanisms of reactions involving short-lived (5–100 μs) intermediate radicals in biologically significant molecules, as well as their structure and properties. For this purpose, pulsed lasers are used to initiate chemical reactions directly within the probe of an NMR spectrometer, combined with high-resolution pulsed NMR methods to detect reaction products. This approach enables the investigation of the influence of magnetic nuclei on the rate and yield of chemical reactions.
The application of the highly sensitive method of Chemically Induced Dynamic Nuclear Polarization (CIDNP) allows for the study of radical intermediates of biochemical processes under conditions close to physiological. Furthermore, measuring the relaxation properties of magnetic nuclear spins makes it possible to track the interactions of these intermediates with biologically active macromolecules.
A prominent example of this research direction is the study of the interactions between small biomolecules—metabolites—and proteins, which opens avenues for assessing their impact on cellular processes and metabolism. In particular, NMR studies of metabolites have revealed their role in protecting cells from DNA damage caused by ionizing and ultraviolet radiation, chemical mutagens, or reactive oxygen species, which significantly influence the rate of organismal aging. This approach also enables the analysis of biochemical processes in tissues such as the eye lens, which is important for understanding the mechanism of cataract development.
