2025
Understanding the specifics of small-molecule binding to proteins is essential for optimizing the pharmacological properties of new drugs and predicting potential side effects. In this work, we present a novel combined approach for identifying ligand-binding sites, such as those of photosensitizers, on proteins. The method is based on a combination of blind docking and experimental data obtained using electron paramagnetic resonance (EPR). The proposed approach enables the generation of detailed, experimentally validated maps of binding sites.
To demonstrate the effectiveness of the proposed method, we investigated the interaction between the transport protein human serum albumin and a series of porphyrin-based photosensitizers that are of major importance for photodynamic therapy. As a result of the analysis, the locations of binding sites were determined for seven compounds whose interaction details had previously remained unclear. Our approach was the first to clearly demonstrate the binding of porphyrins to noncanonical regions of albumin at multiple sites simultaneously.
In addition, the proposed method overcomes the limitations of fluorescence spectroscopy, whose results may be misinterpreted in the presence of multiple binding sites. The strategy we developed opens fundamentally new possibilities for the analysis of protein complexes with potential drug candidates, making the drug development process significantly faster and more efficient.
The article based on this work, published in JACS, was recognized as an “Editor’s Choice” by the American Chemical Society and also received the “Best Paper Award” from the International EPR Society.
Photocatalytic materials capable of generating hydrogen from water under sunlight irradiation are currently being intensively investigated. However, in many cases, the detailed mechanisms of the photophysical and photochemical processes underlying hydrogen evolution remain poorly understood. In this work, we developed and studied novel heterojunction photocatalysts based on tungsten oxides and the chromophore ZnTCPP (meso-tetra(4-carboxyphenyl)porphyrin). It was shown that hydrogen evolution in ZnTCPP/WO₃ composites exceeds the sum of the individual yields of their components, indicating successful synergy within the heterojunction.
In addition, we applied a combination of continuous-wave electron paramagnetic resonance (EPR) spectroscopy and time-resolved EPR spectroscopy to identify intermediate excited states, investigate electron transfer, and analyze side reactions in the ZnTCPP/WO₃ photocatalyst series. The EPR data were analyzed together with the hydrogen evolution efficiency, providing insights into further strategies for improving the photocatalytic performance of these materials.
Nitrogen dioxide (NO₂) is one of the major atmospheric pollutants generated by vehicle exhaust and industrial emissions. Due to its high chemical reactivity, most conventional sorbents used for NO₂ capture rapidly degrade, limiting their practical long-term application.
In this work, we developed a low-cost and scalable sorbent based on the metal–organic framework MOF-801 for efficient NO₂ removal from gas mixtures. Using a combination of electron paramagnetic resonance (EPR) spectroscopy, infrared spectroscopy, and breakthrough experiments, we revealed the mechanism of NO₂ adsorption inside the porous material. The study showed that NO₂ is initially chemisorbed with the formation of nitrates and nitrites, followed by accumulation of additional NO₂ species within the pore structure.
A key achievement of the work is the development of a simple regeneration strategy using formic acid, which restores the porous structure of MOF-801 and enables repeated reuse of the material without significant loss of performance. As a result, a complete adsorption–desorption cycle suitable for multiple regeneration rounds was successfully demonstrated.
The proposed strategy combines scalable synthesis, low-cost regeneration, and high stability, providing a promising platform for the development of next-generation NO₂ sorbents for practical environmental applications.
Precise and rapid oxygen sensing is crucial in a wide range of applications, from industrial process control to environmental monitoring and medical devices. In this proof-of-concept study, we present a new type of gas-phase oxygen sensing system that combines electron paramagnetic resonance (EPR) detection with a custom-designed sensing material: a metal–organic framework ZIF-8 composite with an embedded nitroxide spin probe. To enhance the sensing performance, we adapted the continuous wave EPR experiment protocol and optimized both the material structure and the gas delivery system. Static and flow experiments with dynamic exchange of the analyzed gas mixture were carried out. The sensing system significantly outperforms commercially available industrial models. It demonstrated reliable detection over a broad oxygen concentration range (0.02 to 95%) and response times from 550 ms to 2 s without sacrificing the accuracy. Due to detection simplicity, the sensor module can be further optimized by embedding it into an EPR-on-a-chip device, reducing the price and the module size. The integration of spin probes into a porous engineered framework offers a powerful approach for developing accurate and tunable oxygen sensors, which can meet the demands of both industry and research.
