Публикации
ЦМТ «Мост»

Drop-coating deposition Raman (DCDR) spectroscopy is a promising approach for enhancing Raman signal sensitivity for dilute biological samples. However, its reliability for the quantitative analysis of multicomponent mixtures remains insufficiently explored due to potential solute fractionation effects during droplet drying. In this work, we investigate the limits of applicability of the DCDR method for quantifying binary mixtures of proteinogenic amino acids. Raman spectra of dried droplets containing individual amino acids and their mixtures were measured and analyzed using a linear combination approach combined with least-squares fitting. As a model system, the L-alanine/l-glutamine mixture was first examined to determine optimal spectral processing parameters and sampling region within the "coffee-ring" structure. The approach was subsequently extended to binary mixtures of L-alanine with the remaining 19 proteinogenic amino acids. The results reveal that estimated amino acid relative concentrations strongly depend on the physicochemical properties of the mixture components, including solubility and molecular mobility, which affect their spatial fractionation during droplet drying. These results provide important insights into the applicability of DCDR spectroscopy for complex biological samples paving the way for future analyses of multicomponent systems under physiologically relevant conditions.

Methylammonium lead iodide is one of the most promising materials for flexible thin-film electronics. Today, flexible MAPbI3 solar cells reach a power conversion efficiency of over 21%. These devices are mostly subjected to small but repetitive loads, such as compression and extension, which are the key factor defining the output properties of a flexible device during its period of use. Here we study how the applied mechanical strain affects the structural and electronic properties of MAPbI3 semiconductor and present the quantitative relationship between the band gap and the magnitude of uniaxial deformation. We reveal that band gap changes under compression originate from an increased overlapping of Pb and I orbitals due to shortened bond lengths and enhanced covalent interaction. The c-axis was discovered to be particularly susceptible to compression, with a 15% strain almost halving the band gap.

Extracellular vesicles (EVs) represent a promising tool for diagnostics and therapy, but high heterogeneity limits their practical use. In this work, a comparative study of the physicochemical properties of native EVs secreted by HEK-293T cells and exosome-like nanovesicles (EMNVs) obtained by extrusion of whole HEK-293T cells was carried out. Using transmission electron microscopy, dynamic and electrophoretic light scattering, and surface-enhanced Raman spectroscopy, the authors found that EMNVs form a more homogeneous population with an average diameter of ~115 nm and a high negative charge (−22.9 mV), whereas native EVs are more heterogeneous in size and have a lower zeta potential (−12.1 mV). Spectral analysis revealed the presence of nucleic acid signals in native EVs and their absence in EMNVs, indicating differences in molecular composition due to different biogenesis mechanisms. The obtained data demonstrate that EMNVs are a more standardized and colloidally stable alternative to native EVs, making them a promising platform for the development of drug-delivery systems.

Metal–organic frameworks (MOFs) constructed from monomers, widely used in commodity plastics, offer a viable route toward sustainable and smart packaging technologies. Here, we report the synthesis of two terbium-based luminescent frameworks, MOF-76(Tb) and UiO-66(Tb), assembled from trimesic and terephthalic acids, which are structurally analogous to species accessible via chemical recycling of plastic waste. Owing to their distinct topologies, thermogravimetric analysis reveals markedly higher thermal stability of UiO-66(Tb), which remains stable up to 460 °C, compared to 300 °C for MOF-76(Tb). While hydrolytic stability tests conducted over 168 h demonstrate sustained luminescence, with an intensity increase by 50 to 100% observed for both MOFs. Structural analysis shows that the one-dimensional MOF-76(Tb) undergoes significant reconstruction under hydrolysis, whereas the highly connected UiO-66(Tb) largely retains its crystallinity. These findings establish UiO-66(Tb) as a robust luminescent marker suitable for long-term deployment in real-life conditions, while the pronounced humidity response of MOF-76(Tb) underscores its potential for sensing and smart packaging applications.

Предмет исследования. Эффект электро-индуцированной генерации второй гармоники в монокристаллическом кремнии с наночастицами золота на поверхности. Цель работы. Создание гибридных наноструктур на основе монокристаллического кремния с наночастицами золота на поверхности полупроводника и демонстрация оптического гистерезиса в процессе генерации второй гармоники от кремния в отсутствии и присутствии металлических наночастиц, поддерживающих плазмонный резонанс. Метод. Конфокальная лазерная сканирующая спектроскопия генерации второй гармоники с источником фемтосекундных лазерных импульсов на длине волны 1047 нм. Основные результаты. Созданы гибридные наноструктуры на основе монокристаллического кремния с наночастицами золота на поверхности полупроводника, а также обнаружено усиление сигнала второй гармоники и проявление петли гистерезиса на графике зависимости сигнала генерации второй гармоники от мощности излучения возбуждения, получены спектральные характеристики рассеяния исследуемых структур. Практическая значимость. Массив гибридных наноструктур может быть использован в качестве элемента с эффектом оптической энергонезависимой памяти.

Physically unclonable functions (PUFs) are a promising solution for anticounterfeiting technologies. However, their mass implementation is limited by fabrication complexity and/or special materials demands, as well as specialized authentication. To overcome these issues, a scalable and sustainable approach for fabricating optical PUF labels is proposed in this work. The approach is based on direct laser metallization (DLM) of deep eutectic solvents on flexible polyimide substrates. The laser-induced reduction of copper precursors produces microstructures made by specially designed templates with stochastic edge morphologies serving as unique unclonable identifiers. A computer vision–based authentication algorithm enables robust recognition, achieving an encoding capacity exceeding 10^465. The created labels can be authenticated using standard microscopes or consumer smartphones with macro lenses. Additionally, created labels were tested for stability and unauthorized copying. The replication attempts using 1200 dpi laser printing reproduced macroscopic outlines but failed to mimic microscopic features, confirming their unclonability. The fabricated labels remain functional after exposure to running water and heating up to 200°C, demonstrating excellent environmental durability. Due to its flexibility, scalability, and low-cost eco-friendly processing, the proposed label design is well suited for integration into flexible and wearable microelectronic systems, providing a practical solution to next-generation anticounterfeit technologies.