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%.
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.
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.
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 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.
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.
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 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.
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.
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.
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.
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.
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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