TY - GEN A1 - Efremenko, Yulia A1 - Mirsky, Vladimir M. T1 - Chemosensitive properties of electrochemically synthesized poly-3-thienylboronic acid: conductometric detection of glucose and other diol-containing compounds under electrical affinity control T2 - Polymers N2 - Due to the presence of the boronic acid moieties, poly-3-thienylboronic acid has an affinity for saccharides and other diol-containing compounds. Thin films of this novel chemosensitive polymer were synthesized electrochemically on the gold surface. The adhesion of the polymer was enhanced by the deposition of a monomolecular layer of thiophenol. The technology was used to fabricate conductometric sensors for glucose and other diol-containing compounds. Simultaneous two- and four-electrode conductivity measurements were performed. The chemical sensitivity to sorbitol, fructose, glucose, and ethylene glycol was studied at different pH and electrode potentials, and the corresponding binding constants were obtained. Depending on the electrode potential, the reciprocal values of the binding constants of glucose to poly-3-thienylboronic acid at neutral pH are in the range of 0.2 mM–1.0 mM. The affinity for glucose has been studied in buffer solutions and in solutions containing the major components of human blood. It was shown that the presence of human serum albumin increases the affinity of poly-3-thienylboronic acid for diol-containing compounds. KW - glucose sensor KW - saccharide sensor KW - chemosensitive polymer KW - poly-3-thienylboronic acid KW - conductometric sensor KW - glucose biosensor Y1 - 2024 U6 - https://doi.org/10.3390/polym16131938 SN - 2073-4360 VL - 16 IS - 13 PB - MDPI AG ER - TY - GEN A1 - Snopok, Borys A. A1 - Nizamov, Shavkat A1 - Snopok, Tetiana V. A1 - Mirsky, Vladimir M. T1 - Agglomeration compaction promotes corrosion of gold nanoparticles T2 - Nanoscale Advances N2 - Engineered nanoparticles are increasingly being used in various areas of human activity. However, the degradation mechanism of nanobodies in harsh environments is still a puzzle for theory and experiment. We report here the results of optical spectroscopy and nanoparticle tracking analysis, quantifying agglomeration and sizing of 50 nm citrate stabilized gold nanoparticles (GNPs) in HCl solutions containing H2O2. The mechanism of a consecutive corrosion reaction of GNPs is discussed within the framework of the near-field approach. We found that the disappearance of single nanoparticles from a suspension does not occur due to their dissolution per se, but is a consequence of the formation of aggregates. The neutralization of electrostatic shielding at high ionic strength allows gold nanoparticles to approach the subnanometer distance within the region of capping defects, at which the Casimir and van der Waals attractive forces dominate. It is suggested that electric field fluctuations in the confined space between highly conductive gold nanoparticles cause complexant-stimulated loss of metal from the core in the contact area. Going beyond the charge screening limitations by constraining the reaction space and reducing the double electrical layer thickness allows for chemical processes flow along otherwise not accessible reaction pathways. Y1 - 2024 U6 - https://doi.org/10.1039/D4NA00109E SN - 2516-0230 VL - 6 IS - 15 SP - 3865 EP - 3877 PB - Royal Society of Chemistry (RSC) ER - TY - GEN A1 - Laurinavichyute, Veronika K. A1 - Nizamov, Shavkat A1 - Mirsky, Vladimir M. T1 - Cyclic voltarefractometry of single TiO₂ nanoparticles in large ensembles in nonaqueous electrolyte T2 - Analytical chemistry N2 - Single nanoparticle (NP) cyclic voltarefractometry (CVR), realized as wide-field surface plasmon resonance microscopy (SPRM) in combination with potential cycling, has been proposed and applied to the in situ study of TiO₂ NPs. Electrochemical activity of TiO₂ is mainly observed outside the electrochemical stability window of water. Therefore, the response of individual anatase (a-TiO₂) and rutile (r-TiO₂) NPs adsorbed on a gold layer was studied in 0.25 M LiClO4 acetonitrile solutions. The use of acetonitrile allows us to exploit a much wider potential window compared to water, while due to the almost identical refractive index (nD = 1.344 and 1.333 for acetonitrile and water, respectively), the conditions of the SPR are not changed. This greatly expands the variety of electrochemical reactions that can be studied by SPR techniques. Cyclic polarization of a-TiO₂ and r-TiO₂ NPs results in pronounced electrochemical and optical responses around −1.55 V and around −1.8 V vs Fc+/Fc, respectively. This specific optoelectrochemical response allows them to be distinguished from other NPs. Based on this difference in characteristic potentials, a mixture of a-TiO₂ and r-TiO₂ NPs can be analyzed by CVR as well. The proposed correction algorithm compensates for the drift in the SPRM background caused by the accompanying formation of insoluble compounds and separates the optical response of the NPs out of the background. The results obtained in the study of this complex system demonstrate the capabilities of the developed analytical method. The CVR can be applied to the quantitative analysis of many other types of NPs in nonaqueous solutions, providing information on the electrochemical properties of each individual particle on the electrode surface. Y1 - 2025 U6 - https://doi.org/10.1021/acs.analchem.4c04181 SN - 0003-2700 SN - 1520-6882 VL - 97 IS - 2 SP - 1160 EP - 1169 PB - American Chemical Society CY - Washington, D.C. ER - TY - GEN A1 - Snopok, Borys A. A1 - Ducke, Jana A1 - Mirsky, Vladimir M. T1 - Recognition of soft agglomerates in liquids : comparison and complementarity upon studying gold nanoparticles by tracking analysis, electron spectroscopy and microscopy T2 - Powder technology N2 - A key part of nanoscience is studying how tiny particles gather together in liquids. However, detecting soft agglomerates in their main population formed by single nanoparticles is challenging, since the pairing can only be revealed through adequate identification. In this study, we investigate the effects of agglomeration 60 nm citrate-stabilized gold by optical spectroscopy, nanoparticle tracking analysis and scanning electron microscopy. Optical spectroscopy is limited in its ability to detect soft agglomerates, indicating their presence only when the plasmonic band is approximated by profiles of different types. Electron microscopy requires optimisation of sampling protocols and substrate choice, but still reflects only the dominant agglomerates presented in suspension. Nanoparticle Tracking Analysis is the only method that allows us to characterise the agglomerates in their undistorted state, displaying their greatest diversity. However, it does not provide any information on their composition and shape. We have shown that a correct workflow leads to good agreement between all three methods with respect to the ratio of the most stable agglomerates and individual nanoparticles in the suspension. A detailed discussion of the observed correlations is presented, allowing us to identify gaps in the theoretical description important for the development of targeted analytical protocols. KW - Soft agglomerates KW - Gold nanoparticles KW - Scanning electron microscopy KW - Nanoparticle tracking analysis KW - Optical spectroscopy of nanoparticles KW - Nanoparticle dimers Y1 - 2026 U6 - https://doi.org/10.1016/j.powtec.2025.121649 SN - 0032-5910 VL - 468 SP - 1 EP - 11 PB - Elsevier BV CY - Amsterdam ER - TY - GEN A1 - Kaya, Berfinsu A1 - Efremenko, Yulia A1 - Mirsky, Vladimir M. T1 - Conductometric chemosensor for saccharides based on thin films of poly(3-thienylboronic) acid : measurements of transversal resistance T2 - Biosensors N2 - Poly(3-thienylboronic acid) (PThBA) has recently been suggested as a conducting polymer with affinity for saccharides. In this study, thin films of this compound were deposited onto gold electrodes. The system obtained was studied as a possible chemical sensor. The measurements were performed by impedance spectroscopy using potassium ferro/ferricyanide as a redox mediator. The thickness of the polymer and the deposition of the adhesive sublayer were optimized to achieve a compromise between the blocking of defects in the polymer layer and the unnecessary increase in the internal resistance of this conductometric sensor. A comparative study of the influence of fructose, glucose, and sorbitol on transversal polymer resistance was conducted. The binding constants for these saccharides were extracted from the concentration dependencies of sensor conductance. Among them, sorbitol showed the highest affinity with a binding constant up to ~15,000 L·mol−1, followed by fructose (~8700 L·mol−1) and glucose (~4500 L·mol−1). In order to exclude the contribution of the analyte tautomers on the obtained binding constants, measurements of ethylene glycol were also performed. The effects of pH and the redox state of PThBA on its affinity properties were studied, revealing higher affinities at alkaline pH and in oxidized state of the chemosensitive polymer. The developed system has the capacity to be applied in chemical sensors and virtual sensor arrays with electrical affinity control. KW - Chemical sensor KW - Saccharide sensor KW - 3-thienylboronic acid KW - Conductometric sensor KW - Electrochemical impedance spectroscopy Y1 - 2025 U6 - https://doi.org/10.3390/bios15100679 SN - 2079-6374 VL - 15 IS - 10 SP - 1 EP - 15 PB - MDPI AG CY - Basel ER - TY - GEN A1 - Sengül, Akant A1 - Reiter, Sebastian A1 - Lotfi, Zahra A1 - Efremenko, Julia A1 - Laroussi, Arwa A1 - Corley-Wiciak, Agnieszka Anna A1 - Ratzke, Markus A1 - Mirsky, Vladimir M. A1 - Wenger, Christian A1 - Fischer, Inga Anita T1 - Titanium nitride plasmonic nanohole arrays with polymer coating : optical properties and their humidity-induced modifications T2 - Optical materials express N2 - The use of titanium nitride (TiN) for the fabrication of plasmonic structures such as nanohole arrays (NHAs) can enable their integration into optoelectronic devices on the silicon (Si) platform, for example, for the realization of on-chip chemical sensors and biosensors based on refractometric transduction. With a corresponding functionalization of the TiN nanohole arrays, these ultra-compact devices can be utilized in the development of various affinity sensors and sensor systems, such as cost-effective electronic noses for the early detection of gases in the food industry or agriculture. In this work, we focus on two types of coating for functionalization of TiN nanohole arrays: electrochemically synthesized poly-N-methylaniline and layer-by-layer deposited polyacrylic-acid/poly-allylamine (PAA/PAH). Our investigation comprises the experimental characterization of the optical properties of TiN nanhole arrays coated with polymer layers of different thicknesses as well as a comparison with simulation results. We demonstrate the potential of our setup sensing applications by measuring changes in optical properties of TiN nanohole arrays coated with PAA/PAH upon exposure to air of different humidity. Y1 - 2026 U6 - https://doi.org/10.1364/ome.578871 SN - 2159-3930 VL - 16 IS - 2 SP - 184 EP - 196 PB - Optica Publishing Group CY - Washington, DC ER -