TY - GEN A1 - Nizamov, Shavkat A1 - Dimchevska Sazdovska, Simona A1 - Mirsky, Vladimir M. T1 - A review of optical methods for ultrasensitive detection and characterization of nanoparticles in liquid media with a focus on the wide field surface plasmon microscopy T2 - Analytica Chimica Acta N2 - Development of nanotechnology and corresponding industries during the last decade resulted in a new challenge for analytical science. This includes an ultrasensitive detection and characterization of nanoparticles of different origin and other nanomaterials in various media, including so complex ones as food, biological or environmental samples. The goal of this review is a systematic analysis of possible approaches and description of physical principles behind these methods. The main attention is paid to optical methods which are considered by authors to be mostly effective for the formulated task. Different approaches for detection and analysis of nanoparticles in a volume as well as of those adsorbed on a surface are discussed. While the technologies based on direct analysis of nanoparticle suspensions belong to the established approaches whose development potential has been in large extent exhausted, the novel technologies based on the surface sensing of adsorbed nanoparticles demonstrate intensive development. Therefore, the final part of the review is focused on the wide-field surface plasmon resonance microscopy. It allows one an ultrasensitive detection and characterization of individual nanoparticles of different origin in complex media and provides numerous possibilities for subsequent chemical identification of the detected particles using a hyphenation with other analytical technologies. KW - Nanoparticles KW - Detection of nanoparticles KW - Characterization of nanoparticles KW - Optical techniques KW - Surface plasmon resonance microscopy KW - Nanoparticle tracking analysis Y1 - 2022 U6 - https://doi.org/10.1016/j.aca.2022.339633 SN - 1873-4324 VL - 1204 ER - TY - GEN A1 - Karačić, Dalibor A1 - Gutić, Sanjin J. A1 - Vasić, Borislav A1 - Mirsky, Vladimir M. A1 - Skorodumova, Natalia V. A1 - Mentus, Slavko V. A1 - Pašti, Igor A. T1 - Electrochemical reduction of thin graphene-oxide films in aqueous solutions – Restoration of conductivity T2 - Electrochimica Acta N2 - Graphene oxide finds applications in different fields of science, including energy conversion. Electrochemical reduction of graphene oxide (GO) significantly improves its conductivity. However, the kinetics of this process depends on the solvent, supporting electrolyte, pH, and numerous other factors. Most studies report the macroscopic views and ex-situ properties of reduced GO. To expand the knowledge about GO reduction, in this study, we used cyclic voltammetry (CV), simultaneous 2 points and 4 points resistance measurement (s24), conductive atomic force microscopy (AFM), and theoretical calculations. Using CV, we demonstrated that the choice of supporting electrolyte (KCl or LiCl) influences the potential range in which electrochemical GO reduction occurs. The activation energy of this process was estimated to be below 30 kJ mol‒1 in both electrolytes, being significantly lower than that required for thermal reduction of GO. Simultaneous in situ s24 resistance measurements suggest that GO films reach a highly conductive state at deep negative potentials, with an abrupt, irreversible switch from non-conductive to the conductive state. However, conductive AFM presents a more exact picture of this process: the reduction of GO films starts locally while the formed conductive islands grow during the reduction. This mechanism was confirmed by theoretical calculations indicating that the reduction starts on isolated oxygen-functional groups over the GO basal plane, while clustered OH groups are more difficult to reduce. The presented results can help in tailoring reduced GO for a particular electrochemical application by precisely controlling the reduction degree and percentage of the conductive area of the reduced GO films. KW - Electrochemical reduction of graphene oxide KW - Supporting electrolyte effect KW - Simultaneous 2-point 4-point resistance measurements KW - Conductive atomic force microscopy KW - Theoretical calculations Y1 - 2022 UR - https://www.sciencedirect.com/science/article/pii/S0013468622002183 U6 - https://doi.org/10.1016/j.electacta.2022.140046 SN - 1873-3859 SN - 0013-4686 VL - 410 ER - TY - GEN A1 - Efremenko, Yulia A1 - Mirsky, Vladimir M. T1 - 3-Thienylboronic Acid as a Receptor for Diol-Containing Compounds: A Study by Isothermal Titration Calorimetry T2 - Chemosensors N2 - The electrochemical activity of 3-thienylboronic acid and its feature to form polymer films makes it a perspective receptor material for sensor applications. The affinity properties of this compound were studied here by isothermal titration calorimetry. A number of different analytes were tested, and the highest binding enthalpy was observed for sorbitol and fructose. An increase of pH in the range of 5.5–10.6 results in the rise of the binding enthalpy with an increase of the binding constant to ~8400 L/mol for sorbitol or ~3400 L/mol for fructose. The dependence of the binding constant on pH has an inflection point at pH 7.6 with a slope that is a ten-fold binding constant per one pH unit. The binding properties of 3-thienylboronic acid were evaluated to be very close to that of the phenylboronic acid, but the electrochemical activity of 3-thienylboronic acid provides a possibility of external electrical control: dependence of the affinity of 3-thienylboronic acid on its redox state defined by the presence of ferro/ferricyanide in different ratios was demonstrated. The results show that 3-thienylboronic acid can be applied in smart chemical sensors with electrochemically controllable receptor affinity. KW - chemical sensors KW - affinity KW - isothermal titration calorimetry KW - 3-thienylboronic acid KW - diol-containing compounds Y1 - 2022 UR - https://www.mdpi.com/2227-9040/10/7/251 U6 - https://doi.org/10.3390/chemosensors10070251 SN - 2227-9040 VL - 10 IS - 7 ER - TY - GEN A1 - Efremenko, Yulia A1 - Mirsky, Vladimir M. T1 - Electrical Control of the Receptor Affinity T2 - Engineering Proceedings N2 - A concept of virtual sensor array based on an electrically controlled variation of affinity properties of the receptor layer was realized on the base of integrated electrochemical chemotransistor containing conducting polymer as the receptor layer. Electrical control of the redox-state of the polymer (polyaniline) was performed in a five-electrode configuration with four electrodes for conductivity measurements and Ag/AgCl reference electrode integrated on the same glass chip. An ionic liquid provided an electrical connection between the reference electrode and chemosensitive material. Conductivity measurements demonstrated potential controlled electrochemical conversions of the receptor material between different redox states. The binding of trimethylamine at three different potentials corresponding to these states was studied. The results demonstrated that both kinetic- and equilibrium-binding properties of the receptor are controlled by the electrical potential, thus providing a possibility to form a virtual sensor array using only a single sensing element. The concept was applied for monitoring fish headspace. Using three characteristics of the sensor response measured at three different redox states of the same sensor material, we obtained signals from a virtual sensor array consisting of nine chemosensitive elements. The sensor displays systematic changes of its nine signals during fish degradation. This approach can be applied also for the electrical control of the affinity of immunoglobulins. Development of new materials with electrically controlled affinity is in progress. KW - conducting polymer KW - affinity KW - virtual sensor array Y1 - 2021 UR - https://www.mdpi.com/2673-4591/6/1/3 U6 - https://doi.org/10.3390/I3S2021Dresden-10084 SN - 2673-4591 N1 - Presented at the 8th International Symposium on Sensor Science, 17–28 May 2021 VL - 6 IS - 1 ER - TY - GEN A1 - Nizamov, Shavkat A1 - Scherbahn, Vitali A1 - Mirsky, Vladimir M. T1 - Detection of Single Sub-Micrometer Objects of Biological or Technical Origin Using Wide Field Surface Plasmon Microscopy T2 - MDPI Proceedings (Journal), Proceedings of the 5th International Symposium on Sensor Science (I3S 2017)) N2 - Detection of nano- and microparticles is an important task for chemical analytics, medical diagnostics, food industry, biotechnology, environmental monitoring and many other fields of science and industry. For this purpose, a method based on the detection and analysis of minute signals of surface plasmon resonance images due to adsorption of single particles was developed. The new technology allows one a real-time detection of interaction of single nano- and microparticles of different origin with sensor surface. Adsorption of each nanoparticle leads to a characteristic diffraction image whose intensity depends on the size and chemical composition of the particle. The number of the nanoparticle - surface binding events per time and surface area characterizes volume concentration. A large monitored surface area of the sensor surface allows one to detect many hundreds events in each frame or totally up to a million particles on the sensor surface, this leads to a very high dynamic range of counting and to a correspondingly high dynamic range in the concentration scale. Depending on the type of particles and experimental conditions, the detection limit for aqueous samples can be below 1000 nanoparticles per microliter. Stable analysis of nanoparticles in very complex environment (fruit juices, wines, cosmetic formulations) was demonstrated. For determination of chemical composition of single nanoparticles separately, the wide field surface plasmon microscopy can be used as a tandem technique. For example, for analysis of technical nanoparticles it can be assisted by electrochemical analysis. In this case, the gold sensor surface is used both for plasmon microscopy and as a working electrode of electrochemical cell. Applying a linear potential sweep to this electrode, adsorbed nanoparticles can be subjected to an electrochemical conversion leading to the change of their refractive index; the value of electrical potential of this conversion characterizes material of the particular nanoparticle. Notably, such analysis is performed simultaneously but independently for each adsorbed particle. The method of wide filed surface plasmon microscopy can be applied for ultrasensitive detection and analysis of nano- and microparticles of biological (bacteria, viruses, exosomes), biotechnological, (liposomes, protein nanoparticles for drug delivery) or technical (metallic, oxides, plastic, etc.) origin. Y1 - 2017 UR - https://www.mdpi.com/2504-3900/1/8/788 U6 - https://doi.org/10.3390/proceedings1080788 VL - 1 IS - 8 PB - MDPI CY - Basel, Switzerland ER - TY - GEN A1 - Efremenko, Yulia A1 - Laroussi, Arwa A1 - Sengül, Akant A1 - Corley-Wiciak, Agnieszka Anna A1 - Fischer, Inga Anita A1 - Mirsky, Vladimir M. T1 - Deposition of Polymers on Titanium Nitride Electrodes T2 - Coatings N2 - The application of titanium nitride (TiN) as an electrode for electrochemical deposition or characterization requires the removal of an insulating layer from its surface. This process was studied and optimized, and the conditions for the complete removal of this layer through treatment with oxalic acid were formulated. The obtained TiN surfaces were used for the deposition of various conducting and non-conducting polymers. Two different approaches were applied: (i) in situ electrochemical synthesis of the main classes of conducting polymers, including polyaniline, polypyrrole, polythiophene, and selected derivatives thereof, and (ii) electrostatically driven layer-by-layer (LbL) deposition of multilayers of oppositely charged polyelectrolytes. The deposited polymers were characterized by electrochemical methods. The electrochemical properties of the deposited conducting polymers and their deposition on the TiN surface were comparable to those of the metallic electrodes. The films produced via LbL deposition exhibited a pronounced influence of the charge of the last deposited polymer on the redox reaction of ferri/ferrocyanide, validating the charge alteration with each successive polymer layer deposition. The studied deposition technologies can be used for the modification of TiN surfaces required in applications of this material in chemical sensors and other devices. Y1 - 2024 U6 - https://doi.org/10.3390/coatings14020215 SN - 2079-6412 VL - 14 IS - 2 ER - TY - GEN A1 - Beisembek, Alisher A1 - Dimchevska Sazdovska, Simona A1 - Mirsky, Vladimir M. T1 - Separation of shifts in surface plasmon resonance into refractive index and thickness of deposited layers T2 - Sensors and actuators. B, Chemical N2 - Routine Surface Plasmon Resonance (SPR) measurements, which are widely applied in affinity (bio)sensors and surface science, do not allow one to separate the obtained SPR signals into the change of the refractive index and thickness of deposited layers. For thin layers the signal is proportional to the product of the layer thickness and the difference in the refractive indices of this layer and of the aqueous media. In this study, we suggest an approach to separate these parameters. It is performed by subsequent measurements in the presence and in the absence of polyethylene glycol (PEG), an inert additive which modifies the refractive index of the liquid phase but do not penetrate into the adsorbed layer. Both parameters were successively determined for human serum albumin (HSA) as well as for anti-HSA IgG in three different settings: i) HSA adsorbed directly onto a gold surface, ii) HSA chemically immobilized on a gold surface coated with a self-assembled monolayer of 1,16 mercaptohexadecanoic acid and iii) chemically immobilized HSA with additional monomolecular layer of anti- HSA IgG antibodies bond to this protein layer. The suggested approach can be applied in most SPR devices with a flow cell for analysis of various adsorbed layers. KW - Surface plasmon resonance KW - Thin layer thickness KW - Refractive index measurement Y1 - 2023 U6 - https://doi.org/10.1016/j.snb.2023.134606 SN - 1873-3077 SN - 0925-4005 VL - 396 ER - TY - GEN A1 - Laroussi, Arwa A1 - Raouafi, Noureddine A1 - Mirsky, Vladimir M. T1 - Electrocatalytical Chemical Sensor for Hydrogen Peroxide T2 - Engineering Proceedings N2 - The fast and selective determination of hydrogen peroxide (H2O2) is of importance not only because of strong interest in this widely applied analyte, but also because of the development of enzymatic biosensors for glucose or other metabolites where the sensor for H2O2 can be used as the transducer. Here, we report on an electrocatalytical amperometric sensor for the detection of H2O2. It is a sensor that consists of a gold electrode covered by a self-assembled monolayer (SAM) with immobilized p-benzoquinone. To provide highly stable immobilization of p-benzoquinone at the distance of effective electron tunneling, a new anchor compound—1,3-dimercaptopropan-2-ol—was synthesized and used for preparation of the SAM. Due to two thiol groups binding gold surface, this compound provides high stability of the SAM. The surface concentration of p-benzoquinone obtained from cyclic voltammetry is 2.5 ± 0.2 × 10−10 mol·cm−2. Cyclic voltammetry and chronoamperometry experiments proved that the immobilized benzoquinone exhibited high electrocatalytic activity towards the decomposition of H2O2. Depending on the used potential range, different sensing modes can be realized. For example, one can measure electrochemical response due to the oxidation of H2O2 at anodic potentials, or due to the reduction of oxygen formed during oxidative decomposition of H2O2. Also, amperometric response at fixed potential of +0.4 V vs. Ag/AgCl corresponding to the oxidation of benzoquinone to hydroquinone was studied. The sensor exhibited a linear response over a concentration range of 0.1–2 mM with a low detection limit of 4.24 µM. The reproducibility of three different electrodes prepared was examined at the H2O2 concentration range from 0.1 till 3 mM, which resulted in a relative standard deviation below 4.2%. KW - self-assembled monolayer KW - p-benzoquinone KW - electron transfer KW - cyclic voltanmetry KW - chronoamperometry KW - hydrogen peroxide KW - electrocatalysis KW - chemical sensor Y1 - 2021 U6 - https://doi.org/10.3390/I3S2021Dresden-10168 SN - 2673-4591 N1 - Presented at the 8th International Symposium on Sensor Science, 17–28 May 2021 VL - 6 IS - 1 ER - TY - GEN A1 - Kolosova, Olga S. A1 - Efremenko, Yulia A1 - Laurinavichyute, Veronika K. A1 - Nizamov, Shavkat A1 - Petrushenko, Serhii I. A1 - Mirsky, Vladimir M. T1 - Poly-3-thienylboronic Acid Nanoparticles: Synthesis, Characterization, and Interaction with Saccharides Studied at the Level of Individual Nanoparticles T2 - ACS Applied Nano Materials N2 - Polythiophenboronic acid (PThBA) combines an affinity for saccharides with the unique properties of conducting polymers. This polymer was synthesized by enzymatic catalyzed oxidative polymerization, characterized by UV–vis spectroscopy in solvents of different polarity and by 1H NMR. A suspension of PThBA nanoparticles (PThBA NPs) was prepared by injecting a methanol solution of PThBA into an aqueous electrolyte. PThBA NPs were characterized by scanning electron microscopy. Nanoparticle tracking analysis and dynamic light scattering were used to study the concentration of the particles and the particle size distribution. The effect of pH on these properties was analyzed and an increase in nanoparticle size was observed at alkaline pH. This effect was explained by electrostatic swelling of the nanoparticles. Measurements of ζ-potentials in the wide pH range showed the presence of acidic groups with a pKa of 8.6; the value of the surface charge at the conditions of maximal deprotonation of these groups was estimated to be ∼70 mC/m2. Changes in the optical spectra of PThBA NPs due to variations in pH and additions of organic solvents indicate transformations between twisted and planar conformations of the polymer backbone. The binding of saccharides by PThBA NPs resulted in a decrease in the size and charge of the nanoparticles. Recently developed wide-field surface plasmon resonance microscopy (WF-SPRM) can simultaneously monitor every single nanoparticle among many thousands adsorbed on a surface. It was used for the first time to study chemosensitive nanoparticles. The described above effects of pH change and saccharide binding described above, monitor were confirmed by using integral techniques in monitoring individual nanoparticles, by WF-SPRM. The pH effects were shown to be reversible. An increase in the affinity of PThBA NPs for saccharides at a more alkaline pH was also observed. A fast recovery of polymer binding sites by a pH decrease was demonstrated. The synthesized and characterized PThBA NPs can be further used for various purposes including analytical assays, chemical sensors, or chemosensitive nanotechnological devices. KW - - KW - conducting polymers KW - chemosensitive nanoparticles KW - saccharides binding KW - affinity control KW - polythienylboronic acid KW - surface plasmon resonance microscopy Y1 - 2024 U6 - https://doi.org/10.1021/acsanm.4c00216 SN - 2574-0970 VL - 7 IS - 10 SP - 11120 EP - 11135 PB - American Chemical Society ER - 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 -