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The interaction of electromagnetic radiation with ordered and disordered arrays of noble metal nanoparticles, leading to the excitation of various modes of surface plasmon states in them, is analyzed. The dipole localized surface plasmon resonance in isolated nanoparticles and the influence of various size effects on its optical response are considered. The effect of dipole-dipole interaction between gold and silver nanoparticles on the optical properties of various nanosized and nanostructured objects is discussed. It is shown that both localized and delocalized (propagated) surface plasmon modes can be excited in composite gold and silver nanosystems, in particular, in porous films. The prospects for the practical application of nanostructures with arrays of gold and silver nanoparticles in sensor technology, surface-enhanced Raman spectroscopy, and modern optoelectronics are examined.

It was shown that acoustic sensors based on a quartz crystal microbalance with thin films of dibenzotetraazaannulene, a series of its peripherally-substituted derivatives, and metal complexes can be used to determine the HCl content of the gas-phase. It was established that the process is irreversible. Specific features of the kinetics of the responses and their changes with increase of the total dose were studied. It was shown that the total dose of hydrochloric acid vapor at high concentrations (ca. 1000 ppm) can be identified and monitored by analyzing a virtual image of the irreversible component of the multidimensional surface of the sensor response obtained by intelligent arrays of the “electronic nose” type with sensitive layers of dibenzotetraazaannulenes.

The kinetic curves and monolayer clusters on a flat surface for cooperative adsorption, where the probability of sticking of the particles depends on the amount of neighbors on the surface, were calculated by nonequilibrium molecular dynamics. It was found that the type of distribution of the sticking coefficients has a large effect both on the dynamic and on the structural characteristics of the adsorption process. It is shown that the most informative algorithm for classifying the adsorption type is based on the dependence of the fractal dimensionality of the surface structure on the degree of surface coverage.

The term “virtual sensors” is relatively new in the field of chemical sensors arrays. Considering the application of this term in the literature we propose to classify virtual sensors as signal-based and sensor-based ones. The idea of sensor-based approach is to control sensor’s functionality by some external factors (i.e. temperature, illumination). Virtual sensor array composed of one real sensor and two virtual ones (the same sensor illuminated in different regions of spectra) was developed on the basis of QCM sensor modified by nanostructured ZnO film. The array has demonstrated high efficiency in discriminating of alcohols. The “virtual sensors” approach opens wide possibilities for the improvement of functionality, flexibility and miniaturization of electronic nose systems.

A model photosensitizer, hematoporphyrin (HP), captured by graphene oxide (GO) nanocarrier with and without the treatment by sulfuric acid was investigated for UV–VIS absorption, luminescence properties and Raman scattering. We demonstrate that combination of optical techniques can be efficiently used to detect an interfacial structure of hematoporphyrine/graphene oxide (HP/GO) nanoensembles. Finally, stable in aqueous media at neutral pH HP/GO nanocomposite were obtained as a result of esterification reaction catalyzed by sulfuric acid. The nanocomposite with stronger absorption and emission represents a layered structure composed of hematoporphyrine oligomers adsorbed on the surface of GO in monolayer through electrostatic and π-stacking interactions. The formation of such hybrid structures, where graphene oxide plays a role of a non-toxic sheet-like nanocarrier, open the way to create a functional nanocomposites with a high level of selective emission and efficient photosensitizing ability utilizing unique graphene properties as singlet oxygen generation enhancer.

On the basis of current trends in the description of adsorption processes in complex media a conceptual analysis was made of the mechanisms of the appearance of nonexponential kinetics (stretched exponential function) in chemical reactions on a surface. A review of approaches ranging from a phenomenological description to a generalized fractal formalism is presented, and it was used to develop a model of adsorption in nonuniform media in terms of the concepts of the reaction space as a topological subject. By “geometric description” of the evolution of the surface reactions it is possible to unify the various types of effect in terms of a reaction space of required dimensionality and to establish a relationship between the parameters of macroscopic kinetics and features of the trajectory of the analyte in the nonuniform environment during its movement toward the receptor center.

The sol–gel method was used to obtain high-brightness crystal phosphors from SrTiO3: Pr3+ producing more than 1800 cd/m2. A ten-fold increase in the intensity of the main luminescence spectrum band at λ = 617 nm by doping SrTiO3: Pr3+ was achieved by adding a ferric ion coactivator (5 · 10–5 mole %). The results indicated a possible mechanism for the enhancement of the Pr3+ ion luminescence in the presence of the coactivator.

Zinc sulfide and zinc oxide films are produced by the pyrolysis of organometallic compounds (MOCVD technique). The objects of investigation are the phase composition, structure, surface topology, and the optical and piezoelectric properties of the films obtained under different process conditions. The composition of the films depends on the purity level of the precursor, substrate temperature (as the temperature grows, the composition varies from ZnS to ZnO), and evaporation rate (with an increase in this rate, the composition changes from ZnO to ZnS). In addition, ZnS turns into ZnO upon annealing at 600°C. In the most perfect ZnS films, which are obtained with the purest precursor, intense edge luminescence (3.64 eV) is observed for the first time at room temperature. Two-phase ZnS-ZnO films obtained from a cheap precursor are characterized by pronounced piezoelectric properties and can be used in designing different piezoelectric and acoustoelectric devices.

A study was carried out on the mechanism of luminescence self-quenching of heterogeneous biological objects using laser irradiation at 532 nm (50 μW/ μm2) in the format of a confocal microscope. Laser irradiation was found to reduce the luminescence intensity of material by a factor of 3–5, which permits us to obtain informative Raman scattering spectra of the dried cellular envelope of yeast. For irradiation times less than ~3-5 min, quenching is probably due either to formation of radiationless complexes of the excited chromophore molecules with the environment (excimers and/or exciplexes) or partial photodecomposition. Longer irradiation times lead to thermal degradation of the samples with the appearance of peaks corresponding to amorphous carbon.

The effect of various concentrations of Pr3+ on the structural and luminescent characteristics of SrTiO3:Pr3+ phosphors synthesized by the sol–gel method was investigated. Maximum intensity of red luminescence (617 nm) for SrTiO3:Pr3+ with excitation by ultraviolet radiation is observed at an effective Pr3+ concentration of 0.2 mole %. It was shown that the addition of aluminum at the optimum Pr3+ concentration leads to deterioration of the crystallinity and reduces brightness of the SrTiO3:Pr3+ luminescence. The reason for the last effect may be the presence of minute amounts of iron impurity in the initial reagents.

The presence of various components in complex biological samples which interact with inhomogeneous sensor surface, results in stretched exponential behaviour of the sensor response. This general concept was demonstrated by surface plasmon resonance (SPR) measurements of virus-antibody complexes from crude plant homogenates on a gold surface, covered with protein A. The development of the viral infection in the plant Nicotiana tabacum was studied by SPR and ELISA (enzyme-linked immunosorbent assay) as an indicative approach; a good agreement between both methods was shown. The correlation between virus concentration and the parameters of stretched exponential law was demonstrated. These results indicate that the parameters have hidden intrinsic properties of the underlying interfacial reactions and give a good basis for a more specific microscopic model. Die Vielzahl von Komponenten in komplexen biologischen Proben, die in Wechselwirkung mit einer inhomogenen Sensoroberflache stehen, fuhren zu einem gestreckten exponentiellen Antwortverhalten von Sensoren. Dieses allgemeine Konzept wurde durch Oberflachen-Plasmonen-Resonanz-Messungen (SPR) an Virus-Antikorper-Komplexen eines rohen pflanzlichen Homogenats auf einer mit dem Protein A bedeckten Goldoberflache untersucht. Die Entwicklung der Virusinfektion in einer Nicotiana tabacum-Pflanze wurde unter Anwendung von SPR und ELISA (Enzyme-linked immunosorbent assay) beispielhaft untersucht, wobei eine Ubereinstimmung der Ergebnisse mit beiden Methoden erreicht wurde. Die Korrelation zwischen der Viruskonzentration und den Parametern einer gestreckten Exponentialfunktion wurde aufgezeigt. Die Parameter enthalten eine versteckte intrinsische Eigenschaft der zugrunde liegenden Grenzflachenreaktionen und ergeben eine gute Grundlage fur die Entwicklung eines genaueren mikroskopischen Modells.

Recent advances in the sample handling techniques as part of analytical workflow of analysis with electronic nose systems are reviewed. Classic approaches of headspace analysis as well as advanced methods of sample enrichment and dynamic separation are considered and summarized. The efficiency of application of different sampling methods for specific analytical tasks is demonstrated. Special attention is paid to the analysis of present trends of searching the approaches aimed to replace time-consuming and expensive sample preparation procedures with alternative techniques, including development of sensors arrays with adaptive selectivity profiles, creation of sensor interfacial architectures with tunable adsorption properties, advanced experimental data coding and use of classic spectroscopic methods for “virtual” sensor array formation.

On the basis of an analysis of current views about plasmonics a conceptual examination of propagating surface plasmon resonance (SPR) in relation to the basic mechanisms and operating forces was undertaken with the aim of defining the characteristics of SPR transducers for analytical applications. A simple model of a sensor system that makes it possible to relate the analytical requirements to the intrinsic physical or mechanical characteristics of SPR is examined. A brief review of modern developments is presented.

A ceramic crystal phosphor SrTiO3:Pr3+,Al was produced by the sol–gel method with annealing at 1250 °C. Study of the structural and optical characteristics of SrTiO3:Pr , Al powders showed the presence of a high-intensity luminescence band with a maximum at 617 nm, the excitation spectrum of which occupies a broad region in the range of 300-400 nm. On the basis of this crystal phosphor a simple optical converter of ultraviolet radiation into the red region was developed. This made it possible to create a simple sensor for ultraviolet radiation with linear calibration characteristics based on standard silicon photocells.

Hybrid organic–inorganic films containing gold nanoparticles were obtained by the sol–gel method by hydrolytic polycondensation of tetraethoxysilane in aqueous solutions of honey containing HAuCl4 with an acidic catalyst (HCl). The films were examined by absorption and Raman spectroscopy (RS), transmission electron microscopy, and atomic-force scanning microscopy. It was shown that enhancement (3–5 times) of the Raman spectra is observed in the region of gold nanoparticle aggregates, and this predetermines the potential of such materials as supports for surface-enhanced Raman spectroscopy.

The optimization of a sensor array for a concrete analytical task is usually concerned with choosing a set of sensors to provide the best classification. In this work, a method for the prediction of the quality of classification by evaluation of the uniqueness of the raw experimental data is proposed. The key feature of the method is the presentation of the response of array as a function of the responses of its sensors. The dispersion of those functions serves as quantitative measure of uniqueness of the experimental data for a given set of analytes. The efficiency of the approach has been successfully demonstrated using both simulated and experimental data obtained from the array of three mass-sensitive sensors. The best conformity of the classification efficiency in cluster analysis with results obtained in the framework of the proposed approach is observed in the case of Langmuir-type adsorption processes.

A study was carried out on the optical properties of multilayered surface structures obtained by the coordination binding of gold nanoparticles to a silver surface by Zr(IV) ions. Such a system displays high absorption capacity in a broad spectral range (200-2000 nm), which is observed visually as an ultra-black coating. A physical interpretation of this effect is attributed to an interaction between plasmon excitations on the silver surface and the gold nanoparticle film separated by a dielectric bridge structure consisting of d-metal ions.

The specific features of elastic scattering of volume waves and surface plasmon polaritons by polycrystalline gold films have been investigated. An analysis of the relative scattered energy, power spectral density of surface roughness, and integral and angular dependences of scattering of waves of different nature indicates a strong nonradiative multiple scattering of surface plasmon polaritons in gold films. When roughness increases, this scattering leads to an increase in scattering isotropy and to a partial loss of structural information about gold films. The analysis of the scattered energy of surface plasmon polaritons with application of the data on multifractal dimension of gold surface indicates also that the radiative scattering of surface plasmon polaritons depends on both the rms surface roughness and the surface wave propagation length.

The effect of the topography of the silver surface on the formation of self-assembling monolayers of 11-mercaptoundecanol was examined. The metal surface was modified by nitric acid in the presence of hydrogen peroxide (deep etching (DE)) or aqueous malononitrile (chemical polishing (PE)). The adsorption properties of the monolayers differ significantly for the DE and PE surfaces and are a function of the ratio of functional hydroxyl groups available for reaction with analyte and hydrophobic segments of the hydrocarbon chain of the molecule. A correlation between the amount of adsorption and the analyte acidity was demonstrated.

The blocking effect of nickel(II) azamacrocyclic complexes in the biospecific reaction between soybean trypsin inhibitor and trypsin and the absence of such a reaction for related copper(II) complexes were established. The efficiency for inhibition of the formation of the protein adduct was found to depend on the substituents in the macrocyclic ligands. In particular, electron-donor oxygen-containing groups lead not only to efficient blocking of this reaction but also possibly to a considerable change in the conformation of the soybean trypsin inhibitor molecule.

A simple procedure is examined for forming a selective sensor coating using mixed self-assembling thiol monolayers functionalized by molecules of the sulfanilamide antibiotic, sulfamethoxazol (SMX). A model is proposed for the interface processes, which accounts for the complex dependence of the adsorption capacity of the coatings obtained on the surface density of the reactive groups and the low adsorption capacity at high reaction site concentrations. The model was supported by competitive inhibition analysis.

By immobilization of protein A on the surface of magnetic Fe3O4 nanoparticles, coated with a tin(IV) hydroxide shell, we have obtained a magnetic nanosorbent selectively interacting with immunoglobulins. We have demonstrated that the sorbent obtained can be used to selectively extract immunoglobulins from biological media.

We consider a simple statistical model for interaction between a macromolecular receptor and a surface functionalized with low molecular weight ligands of the same type. For the example of the reaction between immobilized sulfamethoxazole and a selective antibody, we have used surface plasmon resonance to demonstrate that the proposed approach is appropriate for describing the dependence of the adsorption capacity on the surface density of the immobilized ligand and its charge state.

A steady-state model of competition inhibitor analysis and its application to the detection of sulfamethoxazole in aqueous solutions (0.01–100 μg/mL) using surface plasmon resonance are examined. An analytical expression (logistic curve) relating the equilibrium response of the biosensor to the concentration of the low-molecular-weight analyte, its immobilized analogue, and the biological receptor was obtained.

Cobalt(II), nickel(II), and copper(II) stearates, their complexes with octadecylamine, and carbon nanotubes were used as coatings on chemical piezoquartz sensors for hydrocarbon vapors. The rapid and reliable identification of hydrocarbons and other volatile compounds is possible by combining an electric nose flow cell with eight piezoquartz sensors and an LKhM-80 gas chromatograph equipped with a short column (nose-chrom device).

The ability to select definite and unique selectivity profile from a variety of molecular organic materials predetermines their using as sensitive layers for cross-selective sensor massifs. However, to gain greater insight into how the instrumental performance depends on various parameters of such sensitive layers there is a need for a flexible, yet cost effective methodology for the estimation of the natural recourses of organic materials to monitor complex gas mixtures. In the present work the use of the cluster analysis method in the ‘fuzzy logic’ concept for the optimization of the cross-selective sensor arrays (‘electronic nose’, EN) is considered. This approach enables to purposefully form the sensor elements arrays with definite chemical functionality optimized for the solution of the specific applied problems. The criteria of the optimization of the sensor response, number and type of the sensor elements are considered with the goal of the improvement of the classification of the pharmaceutical products of the wide use. On the base of analysis of the response kinetic peculiarities the physical mechanisms were considered, which determines the peculiarities of the adsorption–desorption processes at the interface. It was shown that adsorption of molecules from complex mixtures decays nonexponentially in general: in a “weak” adsorbers films it is exponential and approaches a stretched exponential for “strong” adsorbers film. Moreover the stretched exponentiality in adsorption–desorption processes can be described in terms of probabilistic model of relaxation based on the self-similarity of distributed random transition rates. We have demonstrated the first application of the stretched exponential low for nonexponential relaxations of QCM sensors with organic sensitive layers. There is a good agreement between molecular structure of materials, interfacial dynamics of sensors and discrimination ability of massifs thereon.

A method is proposed for the modification of metallic gold surfaces by self-organization of a nickel(II) macrocyclic complex containing a thiol substituent. Effective blocking of biologically active soybean trypsin inhibitor by the immobilized complex was observed. The prospects of using the given surface to create sensitive elements for sensors capable of detecting both small molecules (thiocyanate ions) and some protein substrates is demonstrated.

A new strategy for the preparation of layer-by-layer inorganic assemblies are discussed which allows simple fabrication of multifunctional thin film on various substrates. The procedure involves alternating layers of the cyanoferrate derivatives with layers of copper ions. A film growth was investigated in situ by surface plasmon resonance (SPR) and characterized by atomic force microscopy (AFM). It was shown that the topography of the surface strongly depends on a number of layers. In particular, the change-over to the formation of 3D aggregates after 12–15 cycles of deposition was observed. It was demonstrated that biological captors, immunoglobulins, can easily be immobilized onto these films in closely packed oriented monolayer, and stable theoretically predicted response was obtained in SPR geometry. This suggests that the functional multilayer built using this approach will have useful application owing to their controllable chemical reactivity.

Some predictions concerning the technological expansion for the multisensor systems are made based on the analysis of the state-of-the-art Electronic Nose technology and correlation between their principles of functioning and the main mechanisms for olfactory reactions in living organisms. Emphasis is placed on the dynamic aspect of such systems performance, in particular, the additional value of the kinetic behavior when forming chemical images for composite multicomponent media using the multisensor arrays.

The possibility has been demonstrated for applying a surface plasmon resonance for detecting plant viruses in real samples. An optimal mode for antiviral immunoglobulin immobilization on sensor surfaces is described. Out of three proposed techniques for sensor surface treatment, namely, unmodified gold surface, gold surface treated with (a) thiocyanate and (b) thiocyanate and protein A (Staphylococcus aureus), the latter was chosen as most suited for retention of the formed native immunoglobulin layer.

On the basis of current trends in the description of adsorption processes in complex media a conceptual analysis was made of the mechanisms of the appearance of nonexponential kinetics (stretched exponential function) in chemical reactions on a surface. A review of approaches ranging from a phenomenological description to a generalized fractal formalism is presented, and it was used to develop a model of adsorption in nonuniform media in terms of the concepts of the reaction space as a topological subject. By “geometric description” of the evolution of the surface reactions it is possible to unify the various types of effect in terms of a reaction space of required dimensionality and to establish a relationship between the parameters of macroscopic kinetics and features of the trajectory of the analyte in the nonuniform environment during its movement toward the receptor center.

Features of the calculation of the autocovariance function (ACF) of an isotropic surface from exper- iments on measuring the angular dependence of scattered light are analyzed. The analytical extrapolation of the experimentally obtained function of power spectral density (PSD) of the surface relief based on the application of an adequate model for its description is shown to improve the accuracy of calculations of ACF. In this case, the mean-square roughness of the surface microrelief determined from the data of total integrated scatter- ing (TIS) allows the quantitative normalization of the ACF to be carried out. In the studies of the structure of a complicated surface (a superposition of isotropic and periodic components), the inclusion of PSD features allows one to carry out adequate statistical analysis by using techniques for calculating the ACF of homoge- neous isotropic surfaces. The answer to this question is in the detailed study of experimentally obtained depen- dences of PSD and identification of their domains corresponding to isotropic scatterers, periodic structures, or characteristic dimensions at the surface. The validity of the proposed approach is confirmed by independent studies with the use of atomic force microscopy (AFM). © 2001 MAIK "Nauka/Interperiodica". δTIS

The most sensitive optical method of interferometry was exploited for determination of changes in the refractive index following the adsorption of biological molecules onto the solid surface. Instead of having two waveguiding arms (the main and the reference) in traditional Mach-Zhender interferometer, two ortogonal TM and TE modes propagating through the SiO2–Si3N4–SiO2 waveguide structure were employed in planar polarization interferometer (PPI). Multiperiodic PPI response was, therefore, formed due to the phase shift between TM and TE modes. A matrix simulation procedure was developed in order to investigate the influence of both the refractive index and molecular layer thickness on the PPI response. Nonspecifical binding of fibrinogen to silicon nitride surface was studied as a model object for PPI testing. The results obtained are in good agreement with the known information about fibrinogen adsorption on the different surfaces. An attempt to introduce the concept of ‘surface molecular concentration and molecular polariziability’ instead of ‘molecular layer thickness and refractivity’ was undertaken.

Specific features of the structure of self-assembled layers of dodecanthiol on the surface of polycrystalline films of gold are investigated with the aim of revealing the effect of the substrate relief on the lateral distribution and the predominant orientation of thiol molecules within the limits of the layer. The analysis of the angular dependence of quasi-elastically scattered light that takes into account the contributions of the geometric roughness of the surface and the inhomogeneity of the dielectric constant to scattering allowed us to establish the correlation in antiphase between the distribution of the thickness of the thiol coating and the height of the relief of the gold surface. The formation of a thiol layer on the surface of polycrystalline gold is a complex process including adsorption, local self-assembly, and a surface-induced distortion of the ordered structure in the regions of minima of the surface relief. The approach proposed here and based on the nondestructive analysis of thin organized coatings can be efficiently applied for the study of specific features of the topography and the prediction of chemical functionality of self-assembled molecular ensembles.

Application of the evanescent wave phenomena (e.g. surface plasmon resonance) in the chemical and biochemical sensors provides both optimal conditions for registration of specific interactions and high sensitivity. At the same time, the stability and reproducibility of parameters of a thin gold film (where the plasmon oscillations occur) are key problems for both (i) optimal transformation of biochemical information into the signal that is convenient for further treatment and (ii) the formation of artificial interfacial architectures. The paper presents results concerning the study of the deposition process temperature regimes influence on optical properties and structure of thin gold films. Morphological and topographic features of the thin film structures were analyzed using X-ray diffraction and atomic force microscopy, respectively. It is shown that the simple procedure of the low temperature annealing (at ~ 120°C) provides optimum parameters of thin gold films in view of their application as physical transducers in optical biosensors. Finally, the SPR transducer was fabricated with high sensitive elements used in the device «PLASMON-4M» elaborated in the Institute of Semiconductor Physics (NAS of Ukraine).

Multifractal analysis is performed for description of the surface topography of thin polycrystalline gold film. Its structure was modified by annealing at different temperatures in the range 20÷200 ⁰C and films were imaged by Atomic Force Microscopy. Image was analyzed as a collection of layers taken parallel to the mean surface. Fractal subsets with different scaling properties were described by multifractal divergence (e.g. the difference between maximal and minimal values of the f (a) spectrum). This allowed to highlight the effect of the temperature of film annealing on the surface structure. We found that fractal diversity jumps down in the temperature range 130÷140 ⁰C. Therefore, phase transition occurs in the system. Below the temperature of the phase transition the surface topography is characterized by high roughness and existence of small-scale irregularities. At critical temperature the surface structure undergoes morphological transition caused by melting of small-scale irregularities. The melting also results in a decrease of the surface roughness due to the flowing down of gold crystallites. A notable feature of the approach is its ability to highlight a possible influence of substrate structure on the adsorption/self-assembling processes at the interface, which may be disturbed by the surface irregularities. The typical and expressive example taken from the self-assembling on the polycrystalline substrate. Particularly, substrate topography determines an order of thiols layers resulting in peculiarities of chemical functionality of obtained material. It was shown that formation of well-ordered monolayers of ω-substituted alkanethiols on gold films occurs only if the freshly evaporated gold films were annealed at temperature more than ca.120 ⁰C. The analysis of surface peculiarities allows suggesting that this behavior is caused by disappearance of short-scale multifractal structures. Therefore, the multifractal analysis opens a new avenue for both characterization and direct prediction of surface properties. Particularly, it gives a hint regarding a formation of the Euclidean two-imensional structures at the multifractal substrates.

The kinetics of adsorption and surface structure of adsorbed layers of the human fibrinogen on the gold surface, determined by Surface Plasmon Resonance (SPR) and Atomic Force Microscopy (AFM) analysis, was employed to probe the lateral distribution and preferred orientation of protein molecules within the monolayer. In this study, special sets of immunoassays are presented for fibrinogen adsorption/conformation analysis. The results show that kinetic parameters of antigen-antibody interac- tions are directly related to the interfacial conformation of fibrinogen molecules. Various interfacial structures of adsorbed fibrinogen aggregates, namely single, bi- and three- molecular aggregates, were obtained using a combination of AFM imaging and SPR analysis. Adsorption of fibrinogen onto the surface of polycrystalline gold is a complex process including surface-induced unfolding, local self- assembly and adsorption, occurring concurrently with n and on the time scale of n each other. This result confirmed the utility of the proposed approach for detecting the spatial distribution and biofunctional properties of specific proteins adsorbed from biological liquids in biosensors.

Evanescent field induced chemical imaging concept has been realized in analytical platform based on the µ-tip-enhanced Raman scattering spectroscopy (µ-TERS). The technique aimed to minimize thermal decomposition of dried biological sample as the result of huge concentration of optical field near the tip by increasing the size of an aperture-less "excitation source". µ-TERS technique is similar to classical biosensor systems based on propagating surface plasmon resonance phenomenon but with sensitive elements a few micrometers in size that can be targeted to the area of interest. The utility of the concept is exemplified by the analysis of dried single cell envelope of genetically modified Saccharomyces cerevisiae yeast cells, which do not have any heat-removing pathways, by water as in the case of the living cell. Practical excitation conditions effective for µ-TERS Raman observation of single layer dried biological samples without photodamage-related spectral distortion have been determined - the allowable limit is above 30s at 13 µW/µm(2). Finally, potential of µ-TERS spectroscopy as new bio-friendly instrumental platform for chemical fingerprinting and analytical characterization of buried nanoscale features is discussed.

Single living Chinese hamster ovary cells on the surface of different substrates have been characterized in-vivo by confocal scanning Raman spectroscopy and conventional optical microscopy. It was shown that both morphology and vibration fingerprint of cells depend on the nature of the substrate material (glass, silicon, bismuth germinate, quartz, lithium niobate, gold, silver, tin dioxide) and related to the specific features of the biochemical status of the cells within interaction area influenced by the growth conditions.

The characteristics of intra- and intermolecular electronic processes in crystalline dibenzotetraazaannulene were established based on an analysis of the electronic absorption spectra of thin films. It was shown that the specific spectral characteristics of this substance are due to its stack structure in the solid state.

We show that an important factor in the mechanism of formation for thin films of organic semiconductors is the change in the temperature gradient in the film as its thickness increases. In this case, an important role information of oriented films is played by both diffusional processes within clusters and by re-evaporation of small crystallites.

The green synthesis of irregular-shaped nanomaterials used for various applications in nanoplasmonics, medicine, and biotechnology creates an economical and environmental challenge. We describe the rapid wet-chemical approach to synthesis of stable and water-soluble gold nanostructues at room temperature. In addition to spherical and road-like nanoparticles, gold decahedra and triangular plates were grown using the one-step synthesis process of HAuCl 4 in the presence of honey, in which main components act as reducing (glucose) and stabilizing (fructose) agents; the mechanism of the process is discussed in details. The requirements for anisotropic phase boundaries for generation of polyhedral gold nanocrystals in solutions are highlighted. The synthesis, morphology, and separation procedure of gold nanoparticles are examined using the techniques of optical spectroscopy, transmission electron microscopy, and atomic force microscopy. We demonstrate that centrifugation can be used for efficient separation of nanoparticles with different shapes from a mixture. It was found that while centrifuging, the spheres sediment at the bottom of the tube, segregating from rods that form a deposit on the side wall, whereas polygons remain in the solution.

The results obtained demonstrate the appll-caointy of nonlinear percolation theory for the description of charge-transfer processes In thin films of organic semiconductors, with the model object being a polycrystal with a system of Intercrystalllne barriers with large dispersion In heights. It was shown that the appearance of non-linear phenomena In electrophyslcal properties of such samples (long-time current relaxations, nonlinear VAC) Is caused by changing of barrier heights distribution under the Influence of external electric field on the filling of structural (defects) or Impurity (adsorbed O2) states.

A study has been made on the behavior of a complex formed by nickel(II) with the amphiphilic macrocyclic ligand 6-n-octadecyl-1,4,6,8,11-pentaazacyclotetradecane on the surface of water, and the Langmuir-Blodgett technology has been used to deposit films of that compound on glass substrates with and without electrically conducting coatings (SnO2). Some optical characteristics of these sandwich structures have been examined.

Competitive inhibition serological assay for detection of the phytoestrogen glycitein (Glyc) was developed using surface plasmon resonance (SPR) technique with protein conjugates and polyclonal antibodies initially designed for the enzyme-linked immunosorbent assays (ELISA). The efficiency of the approach to the quantification of the soy isoflavone glycitein in water was investigated using the competitive reaction of analyte (free Glyc)and immobilized Glyc-BSA-conjugate with polyclonal antibodies. It was shown that the efficiency to detect Glyc drastically depends on the pH level of the probe solution. With the decrease in pH from 7.4 to 4.0, (i) the affinity of the specific reaction increases and (ii) the level of unspecific sorption becomes saturated. Non-specific adsorption to a SPR sensor surface obscures the specific component and shaded specific response at higher pH (6.0-7.4) when used serum for the quantification of specific analytes. The standard curves obtained in acidic solutions (pH 4-5) indicate that the linear part of the dependence completely covers the range between detection limit (0.1 μg/ml) and Glyc solubility in water (0.9 μg/ml). The difference in SPR- and ELISA-based analytical protocols as well as the requirements for increasing the efficiency in quantitative SPR analysis using purified antibodies is discussed.

The sensitivity of surface plasmon resonance (SPR) transducers depends on the thickness and spatial organization of interfacial structures at their surfaces. This is because the response of the SPR sensor is determined by integrating the distance-dependent refractive index (spatial interfacial architectures), weighted by the square of the electromagnetic field, from zero to infinite distance. The effect of SPR transducer sensitivity variation on the accuracy of SPR analysis is considered. Our quantitative estimation (based on the results of refractometric studies) gave a value for sensitivity variation of about 3% for the formation of a self-assembled thiocyanate layer or a trypsin-soybean trypsin inhibitor surface complex. The estimated accuracy in measured variation ( i.e. , by 0.01) for the refractive index of the external medium was 3 × 10 −4 . This restriction, which follows immediately from the physical mechanism of the SPR phenomenon, should be taken into account when analyzing data obtained with the above technique.