The paper describes the results of Raman spectroscopy and SERS for the study of fluorescent components of Baltic amber via the extraction method. Using SERS, it was possible to confirm in amber: tetracene and benzanthracene and others components. It has been shown that SERS methods are effective for the detection of aromatic and non-aromatic compounds. SERS be used to distinguish between different types of amber and isolate the necessary amber components. The obtained results are promising for compiling spectral maps of ambers for their possible classification by their place of origin and age.
Paper performs results of portable SERS system for human platelets investigation. Platelets were divided to 2 groups: with acute coronary syndrome on therapy and without therapy. Spectral in groups have been investigated. An analysis of experimental data showed that changes in the SERS spectra of human platelets during therapy may be associated with changes in the amino acids (phenylalanine, tyrosine and tryptophan).
The paper performs results of the use of machine learning methods to differentiate SERS spectra in patients with and without cardiovascular pathologies. Approaches were applied to processing spectral data arrays consisting of 1266 spectra for various groups of patients: healthy patients, patients with pathology of cardiovascular diseases, healthy patients receiving therapy, and patients with pathology of cardiovascular diseases receiving therapy. The applicability of the random forest algorithm for classification problems were shown. Potential spectral biomarkers of differences between the groups of patients on whom these algorithms were tested were identified. The achieved classification accuracy using the random forest spectra algorithm for the groups of healthy patients without therapy and patients with cardiovascular pathology without therapy was 83.4%. When classifying the presence of therapy in healthy patients (control), the accuracy was 76.26%; in patients with cardiovascular pathology, the accuracy was 70%.
This study demonstrates the possibility of using the SERS method to detect methotrexate (MTX) molecules in the blood plasma of patients in concentrations up to 10-6 M. The paper performs investigation for samples from patients who took the drug at different doses. Borosilicate glasses coated with silver nanoparticles were used as the surface. We analyzed the differences between the spectra of patients after taking medication and healthy volunteers without taking medication. The characteristic maxima of methotrexate were determined.
Tuberculosis is still one of the leading causes of death in the world. The COVID-19 pandemic increased the number of newly diagnosed cases, bringing it to 6.4 million in 2021, the number of deaths raised up to 1.4 million. An estimated 10.6 million people fell ill with TB worldwide in 2021, an increase of 4.5% from 10.1 million to 10.6 million was detected. Since the diagnosis of tuberculosis pathology can reach a sufficiently large amount of time, the task of rapid identification of both tuberculosis pathology and the antibiotic resistance of the mycobacterium becomes paramount. Methods based on real-time PCR are used as classical microbiological technologies, however, they have significant limitations in the number of antibiotics for determining resistance. As the vibration spectra (IR or Raman) of Mycobacterium tuberculosis cell is complex and it is difficult to find specific biomarkers for cell fast differentiation.
This study demonstrates the possibility of the surface enhanced Raman spectroscopy (SERS) method to determine concentrations of methotrexate (MTX) in human plasma. This method makes it possible to detect low concentrations of methotrexate in biological samples with relatively inexpensive portable equipment. The SERS signal may be greatly enhanced using nanostructured plasmonic materials which will make this method highly sensitive, selective and productive. The use of SERS to perform a therapeutic drug monitoring procedure is a promising method because of its extreme sensitivity, specificity and speed of analysis.
The drug resistance of Mycobacterium tuberculosis (MbT) remains a serious challenge to global public health as extensively drug resistant tuberculosis usually leads to a lethal outcome. In the case of diseases with resistant strains, it is extremely important to identify a specific strain as soon as possible in order to start an adequate therapy. We continue investigation of deactivated M. tuberculosis strains of the Beijing family by Raman spectroscopy method. Strains under the study had different drug sensitivity: sensitive, multi and extensively drug resistant. Samples were investigated by Surface-Enhanced Raman spectroscopy using 785 nm diode pumped laser excitation source in fingerprint region. As a result, both glutathione bands and DNA methylation using 5-methylcytosine spectral biomarkers has been investigated. These differences distinguish between drug-sensitive and drug-resistant strains and also between strains. We suppose that the obtained results can be useful for new fast diagnostic tools development for determining various MbT strains in clinical medical practice.
The paper describes the results of finite-difference time-domain (FDTD) mathematical modeling of electromagnetic fields distortion near the planar SIO2 surfaces modified with gold nanostars. The calculated field values were converted into the electromagnetic field enhancement coefficient and the surface-enhanced Raman scattering (SERS) intensity. Prospects of the theoretical approach for planar SIO2 surfaces modified with gold nanostars modeling to evaluate optimal field amplification and light-scattering parameters have been shown. The presented approach could be applied as a basis for performing methods of controlled synthesis of effective SERS-based biocompatible sensors.
Thrombus formation issues play an important role in the occurrence, diagnosis and treatment of cardiovascular diseases. The inhibition of platelet aggregation is currently the main therapeutic approach in treatment and prevention of cardiovascular diseases. Understanding the platelet structure and its spectral response to the antiplatelet therapy is the key to personalized medicine today. According to the World Health Organization (WHO) reports, cardiovascular deceases have been remaining the leading cause of death at the global level for the last two decades. The number of deaths has been increased up to nearly 9 million in 2019 [1]. The COVID-19 pandemic has resulted in cardiovascular decease (CVD) increase, which caused deaths in many countries [2-3]. The paper presents studies of the fluorescence intensity of aromatic amino acids namely tyrosine (Tyr) and tryptophan (Trp) in the presence of spherical rhodium and platinum nanoparticles (Rh and Pt NPs).
The effect of the thickness of the polyvinyl alcohol film on the position of the plasmon maximum at the modified titanium-dielectric interface was investigated. The integration of bismuth oxide, thulium oxide, as well as their mixtures into thin polymer films (thickness of up to 1.3 μm) was carried out. It was established that the spectral shift of the plasmon maximum into the red region of the spectrum is due to the roughness features of the titanium surface as a result of anodizing and due to the thickness of the PVA film. The presence of the overlap in the reflection spectra of thulium oxide and bismuth oxide has been established, which leads to a complete leveling of the spectral band of thulium oxide in the region of 350 nm.
Recently, optical methods have become one of the main tools for biomedical applications and have made significant progress in the field of clinical evaluation [1]. A number of natural tissues were studied using spectroscopic methods, including Raman spectroscopy [2, 3]. These vibrational spectroscopy methods are relatively simple, reproducible, do not destroy tissue, and require only small amounts of material (from micrograms to nanograms) with minimal sample preparation. In addition, these methods provide information at the molecular level, allowing the study of functional groups, bond types, and molecular conformations. Spectral bands in vibrational spectra depend on the molecule and provide direct information about the biochemical composition. These bands are relatively narrow, easily resolvable, and sensitive to molecular structure, conformation, and environment. A necessary part of the practical study of any sample is the theoretical prediction of the result in order to better understand the structure of the analyte. This part of the analysis is necessary for a more accurate selection of shooting parameters and a visual representation of the expected result. One of such prediction methods is mathematical modeling. This paper presents the results of studies of SERS spectroscopy of strains of mycobacterium tuberculosis strains and their comparison with theoretical Raman spectra of organic compounds, which were chosen as amino acids (L-histidine), tripedtide (glutathione), and carboxylic acid (citric acid).
In this paper, the plasmon resonance splitting on the anodized modified titanium has been studied. The plasmons absorption process in the permittivity functions spectra and reflectance spectra of p- and s-polarized light on the titanium oxide surface have been analyzed when the surface roughness parameters are changing. The surface roughness values were also estimated in this paper. Spectral features of the negative refractive index in the area of surface plasmon generation on the rough titanium-oxide film interface have been also presented in this paper. Surface roughness parameters are also determined. The upconversion luminescence enhancement of the ytterbium oxide on the rough titanium surface was observed in this work.
This article is a continuation of research in the field of modeling nanoparticles by various FDTD methods. This article clarifies what geometrical parameters are necessary to obtain the highest value of the elec tric field for core-shell particles with a gold (Au) core with a silicon (SiO2) shell; the other part is related to the modeling of silver nanorods (Ag). Both simulations were performed under the action of one plane polarized wave 𝜆 = 532 nm. Parameters such as the height of the rod, the radius of the cross section of the rod were varied; for the core-shell particle, the radius of the particle and the thickness of the SiO2 layer were varied. The analysis of the values of the electric (E) field component of these particles is carried out and compared with each other. The advantage of theoretical modeling by the FDTD method using our algorithm is shown. The presented data can be used as a basis for controlled chemical synthesis of spherical nanoparticles.
This paper describes a detailed study of spectral and time-resolved photoprocesses in human platelets and their complexes with platinum (Pt) nanoparticles (NPs). Fluorescence, quantum yield, and platelet amino acid lifetime changes in the presence and without femtosecond ablated platinum NPs have been studied. Fluorescence spectroscopy analysis of main fluorescent amino acids and their residues (tyrosine (Tyr), tryptophan (Trp), and phenylalanine (Phe)) belonging to the platelet membrane have been performed. The possibility of energy transfer between Pt NPs and the platelet membrane has been revealed. Förster Resonance Energy Transfer (FRET) model was used to perform the quantitative evaluation of energy transfer parameters. The prospects of Pt NPs usage deals with quenching-based sensing for pathology’s based on platelet conformations as cardiovascular diseases have been demonstrated.
The Mycobacterium tuberculosis (MbT) drug resistance remains a serious problem for global public health and usually leads to a lethal outcome. Precise and rapid identification of a specific MbT strain is vital for the appointment of antituberculosis therapy. We continue investigation of deactivated MbT strains of the Beijing family by Raman spectroscopy method and focus on Raman spectra analysis for the identification of potential biomarkers for different MbT strains. . We have studied extrapulmonary Beijing strain with XDR resistance. Samples were investigated by Raman spectrometry with He-Ne (λ=633 nm) laser excitation source in the «fingerprint» region. As a result, new spectral features were determined. They describe spectral discrimination between drug-sensitive and drug-resistant strains identified for extra-pulmonary forms of tuberculosis. We suppose that the obtained results can be useful for new diagnostic tools development for the identification of different MbT strains in clinical and research practice.
This work presents the process of creating laser-induced surface structures by fs laser radiation with circular polarization and the study of their optical properties by ellipsometry method. This report presents SEM images of the Cu and Cu/Au surfaces and the studies of spectral features of dielectric permittivity function and reflection coefficients of s- and p-polarized light.
This paper presents the process of creating a gold surface modified by periodic structures deposited by femtosecond laser radiation by two different geometry. The refraction processes of s- and p-polarized light on the gold structured surfaces with the changes in the dielectric permittivity function were studied and compared in this paper. The presence of surface plasmon generation on the rough gold surface in visible region at two frequencies has been established in this work.
The paper continues [12] the Finite-Difference Time-Domain (FDTD) mathematical modeling method application of electric field distortion near the surface of spherical gold nanoparticles functionalized by two shells: water shell as a model substance for a drug and SiO2 as a capsuling silicon polymer. During the simulation, parameters such as particle size, the thickness of surface layers, the wavelength of exciting radiation, and the dependence of the effective amplification of the E component of electromagnetic field on the thickness of the polymer and water layers were investigated. The prospects of the theoretical approach of core-shell complexes for theranostics tasks are shown. The data presented can be used as a basis for controlled chemical synthesis of spherical nanoparticles.
This paper performs detailed study of Raman scattering for platelets mixed with gold nanoparticles in presence with R6G molecules on quartz surface. Spectral properties of main spectral bands corresponding to proteins and dye in the complexes with gold nanoparticles have been performed. The perspectives SERS for applications in modern physics and biophotonics have been shown. Results of the study can be applied for SERS detection and investigation of blood components such as cells and platelets. Paper describes characteristic maxima of different cell components and its identification in platelets.
The paper performs Finite-Difference Time-Domain (FDTD) mathematical modeling method application of electric field distortion near the surface of rough gold surfaces. During the simulation, parameters such as particle size, nanoparticles height, the effective amplification of the E component of electromagnetic field on the surface morphology were investigated. The prospects of the theoretical approach of rough surface modeling for sensory purposes tasks are shown. The data presented can be used as a basis for controlled nanolithography fabrication of gold rough surfaces.
The article presents the results of the SERS study of fluorine-containing dye 6G (R6G) adsorbed onto quartz surfaces modified with gold nanoparticles (NPs). A new technique for quartz glass modifying with hydrosols of gold NPs of various shapes has been developed. The possibilities of its application to implement SERS effect for R6G molecules have been shown. In this work, we synthesized hydrosols of spherical gold NPs (nanospheres) and rod-shaped NPs (nanorods (NRs)) and studied their optical and morphological properties. The SERS spectra of R6G molecules on NP modified quartz glasses have been obtained as well as the SERS enhancement factor has been calculated.
Optical properties (reflection, refractive index, real and imaginary part of permittivity function) of rough titanium surfaces fabricated by anodizing method at different anodic voltage have been studied. It is shown that a negative region in the visible wavelength range is observed on a rough titanium surface in the refractive index spectrum; its minimum appeared to be red-shifted shifted with surface roughness increase. These optical-nonlinear effects are studied by means s- and p-polarized light reflection coefficients spectra and permittivity spectra registration. It is also shown that the generation of surface plasmon oscillations in the visible spectral region on the rough titanium surface is possible. Excitation of surface plasmons is found to be accompanied by redistribution of the incident electromagnetic energy on the surface and leads to various nonlinear effects including negative values of the refractive index.
The paper presents the results of FDTD (Finite-Difference Time-Domain) mathematical modeling of electromagnetic fields distortion near the surfaces of multilayered spherical gold nanoparticles (NPs). NPs were functionalized by two shells: water as a model substance for a drug and SiO2, as a capsuling polymer. The field values were converted into the coefficient of the effective signal for Surface-Enhanced Raman Scattering (SERS). During the simulation, parameters such as NP size, thickness of surface layers, wavelength of exciting radiation and the dependence of the effective amplification of the electromagnetic field on the thickness of the polymer and water layers were studied. The prospects of the theoretical approach of nanocomplexes for problems of theranostics have been shown. The presented approach could be applied as a basis for performing methods of controlled chemical synthesis of colloidal theranostics NPs.
Paper performs results of SERS-active surfaces fabrication for Raman bacterial cells analysis. Based on FDTD simulation, the synthesis of colloidal gold nanoparticles (NPs) with the size range of 10 – 100 nm has been performed by the following methods: a) femtosecond laser ablation of a plate in a liquid; b) chemical reduction from tetrachloroauric acid trihydrate (HAuCl4). Optimal sizes and shapes of the particles with a maximum of plasmon absorption in the range 500 – 800 nm have been determined by numerical simulation. For NPs deposited on quartz glass with rodamine 6G (R6G) and E. Coli bacterial cells, SERS solutions have been tested.
This paper describes detailed study of single human platelet and can be used for rapid and early structure changes and biomarkers identification in individuals with cardiovascular decease (CCD) pathology in vitro. The obtained data include analyzed Surface-enhanced Raman spectra (SERS) of human platelets taken from healthy individuals and individuals with cardiovascular pathology. Paper describes characteristic maxima of different cell components and its changes in platelets.
This paper describes detailed study of photoprocesses in bovine serum albumin, silver nanoparticles and Rhodamine 6G (R6G) dye complexes using plasmon-enhanced fluorescence effect. Fluorescence spectroscopy analysis of bovine serum albumin molecules in systems doped with silver nanoparticles and rhodamine 6G has been performed. The perspectives of plasmon-controlled photoprocesses in the model complexes for applications of modern physics and biophotonics were shown. Investigations both tryptophan and tyrosine fluorescence of BSA in the complex has been investigated. Experimental concentrations of protein, dye and nanoparticles at which a stable plasmon-enhanced fluorescence effect was observed. Results of the study can be applied for labeling and configuring drug delivery systems for investigation of small blood components investigation such as platelets.
This paper perform the results of studies on the development of a simple methodology for creating hydrosol-modified silver and gold nanoparticles with a size of 44 nm (silver) and 54 nm (gold) quartz surfaces for sensory purposes. Proposed surfaces is able to perform the effect of Surface-enhanced Raman scattering (SERS) of light by dye molecules of Rhodamine 6G. It was shown that the order of amplification of the Raman signal by surface plasmons of silver and gold nanoparticles for Rhodamine 6G dye molecules can reach orders of magnitude 102 times. A method for the controlled synthesis of silver hydrosols by methods of reducing sodium salt AgNO3 with sodium citrate and femtosecond laser ablation for gold is proposed. The prospects of such systems for obtaining spectra of the molecular structure of dyes are shown. The results of this work, in the future, can be used to analyze chemical compounds of low concentrations, macroscopic biological objects like bacterial cells and blood components.
This work presents the dependences of the absorption intensity of acid-soluble chitosan biopolymer films in the infrared region of the spectrum on the concentration of silver and gold nanoparticles of different morphology. The interaction mechanisms in the vibrational spectra overlapping area of silver nanoparticles and chitosan molecules (2500-3500 cm-1) were observed. The influence of metal nanoparticles on dipole moments of OH- , CH - chitosan molecule oscillation groups was established. This interaction leads to a linear increase of the infrared absorption intensity with an increase of the silver nanoparticles concentration, synthesized by citrate and borohydride methods. The presence of silver and gold ablative nanoparticles in the chitosan films demonstrates the infrared absorption intensity exponential decrease with metal nanoparticles concentration.
The optical processes of plasmonic quenching of rhodamine 6G (R6G) molecules fluorescence in polyvinyl alcohol dielectric films formed on rough silver (Ag) surfaces were researched. The depth of penetration of the surface plasmon field into the dielectric film with R6G molecules is calculated. The angular and spectral-kinetic characteristics of dye molecules fluorescence decay on rough Ag surfaces are determined.
In this study, the optical properties of glycated (HbA1c) and non-glycated (Hb) hemoglobin are compared using refractometry, fluorescence and Raman spectroscopy. The fluorescence measured at an excitation wavelength of 270 nm indicates differences in the molecular structure of hemoglobins. Analysis of the spectral shift of Raman spectra also showed variations indicating differences in their molecular structure. The refractive index measured in the visible and near IR regions for different temperatures allowed for quantification of mean values of temperature increment, which are quite different as dn/dT= –(1.03 ± 0.05)×10–4 °C–1 for Hb and – (1.37 ± 0.07)×10–4 °C–1for HbA1c.The data obtained in the work can serve as a basis for further study of the optical properties of glycated hemoglobin and other glycated proteins.
The article explores the influence of plasma energy of ytterbium nanoparticles on the fluorescent and absorption characteristics of the porphyrin molecules (Ethioporphyrin) in methylcellulose films. There has been ascertained the presence of plasmon energy transfer in the porphyrin-cluster system of the ytterbium nanoparticle at the wavelengths of fluorescence registration. The values of the increase in percentage proportion were defined. It was demonstrated that with the clusters concentration increasing the optical density of porphyrin molecules and fluorescence intensity increases.
In this paper by the methods of Raman spectroscopy, a drop of the evaporating liquid of Human Serum Albumin with the Rhodamine 6G dye molecules in the presence of silver nanoparticles obtained by laser femtosecond ablation in water was studied. In the Raman spectra, an increase in the intensity of scattering of dye molecules with silver nanoparticles the addition of protein molecules was recorded. We suppose that the observed effect is associated with the diffusion and thermal processes in the drop arising during laser excitation.
The optical processes of plasmonic enhancement of rhodamine 6G molecules fluorescence in dielectric films of polyvinyl alcohol deposited on a rough silver surface have been studied. The reflection coefficients of the polarized light components on rough silver surfaces have been determined by means of spectral ellipsometry and spectrophotometry methods. Two kinds of silver surfaces were used: without and with anodizing at current density of 5 mA/cm2 of 0.5 μm layer. The plasmon spectrum appeared to be red-shifted after polyvinyl film deposition onto the silver plate. I was shown that the silver-dielectric interface roughness affects the position of the reflected light spectrum maximum to 360 – 400 nm range due to the dielectric polarizing effect.
Anna Tcibulnikova, Igor Degterev , Valery Bryukhanov, Matheus Mantuanelli Roberto , F. D. Campos Pereira, M. A. Marin-Morales, Vasily Slezhkin, Ilya Samusev
We have been searching for new photosensitizers (PS) for photodynamic therapy (PDT) of cancer based on extracts from Amazonian plants since 2009. In this paper, we demonstrate that, under certain conditions, the extract from fruits of the Amazonian palm Euterpe oleraceae (popular name Açaí) can serve as a PS for PDT treatment of murine breast cancer cells (4T1 cell line). We have been first to show directly that the photodynamic effect of plant PS is due to singlet oxygen.
The presence of plasmon resonance in the region of 375 nm for ytterbium nanoparticles obtained by laser ablation in the
stabilizer of AOT in heptane is established in the work. The dimensions of the ytterbium nanoparticles are determined by
the dynamic scattering method. Raman spectra and absorption spectra were measured in the IR region. Characteristic
vibration frequencies for ytterbium nanoparticles and scattering bands for a pure ytterbium metal surface are determined.
We have developed a methodology for the study of deactivated strains of Mycobacterium tuberculosis. Strains of the Beijing species obtained from pulmonary patient secrete (XDR strain) and reference strain (H37Rv) were investigated by Raman spectrometry with He-Ne (632,8 nm) laser excitation source. As a result of the research, the optimal experimental parameters have been obtained to get spectra of mycolic acids, which are part of the cell wall of mycobacteria.
The study of the luminescence of CdZnSeS / ZnS quantum dots (QDs) absorbed on the rough surface of a silver film, including the energy transfer between human serum albumin molecules, isolated from the blood plasma of healthy and infected with sepsis patients, was performed by spectral-kinetic methods.
In this paper we perform results of conformational analysis of septic human serum albumin (HSA) carried out by Raman spectroscopy (RS), infrared (IR) spectroscopy and fluorescent spectroscopy. The main vibrational groups were identified and analyzed for septic HSA and its health control. Comparison between Raman and IR results were done. Fluorescent spectral changes of Trp-214 group were analyzed. Application of Raman, IR spectroscopy, fluorescent spectroscopy for conformational changes study of HSA during pathology were shown.
The plasmonic enhancement and quenching of phosphorescence and fluorescence of the anionic (eosin) and cationic (rhodamine 6G) dyes have been studied in various environments: silver nanoparticles of silver hydrosol citrate in water, in polymer films and on the surface of nanoporous silica in order to determine the kinetic and spectral effects on the dye luminescence. Depending on the silver nanoparticles concentration both the enhancement and quenching of the dyes phosphorescence and fluorescence have been detected. The mechanism of interaction between the excited molecules and silver nanoparticles has been discussed.
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