Antonina Naumenko

Biosynthesis of cadmium sulphide quantum dots by using Pleurotus ostreatus (Jacq.) P. Kumm

The development of ‘green’ technologies in nanoparticle synthesis is of considerable importance to broaden their biological applications. Cadmium sulphide nanoparticles are considered very promising in applied chemistry, bioscience and medicine. The aim of this study was to develop an efficient, easily reproducible and environmentally friendly method for biosynthesis of cadmium sulphide quantum dots based on the usage of mycelium of the basidiomycete fungus Pleurotus ostreatus. By incubating P. ostreatus mycelium with inorganic cadmium sulphate and sodium sulphide, we synthesized stable luminescent CdS nanocrystals. They showed absorption peaks at 453 nm (ultraviolet–visible spectrometry) and a main luminescent peak at 462 nm. Transmission electron microscopy revealed that the obtained quantum dots were of a spherical shape and predominantly from 4 to 5 nm in size. The electron diffraction pattern confirmed the wurtzite crystalline structure of the synthesized cadmium sulphide quantum dots. The obtained results confirm for the first time that the system based on basiodiomycete fungi could be considered promising for synthesizing semiconductor quantum dots.

Dextran-Polyacrylamide as Matrices for Creation of Anticancer Nanocomposite

Drug targeting to specific organs and tissues is one of the crucial endeavors of modern pharmacotherapy. Controlled targeting at the site of action and reduced time of exposure of nontargeted tissues increase the efficacy of the treatment and reduce toxicity and side effects, improving compliance and convenience. Nanocarriers based on the branched copolymers dextran-graft-polyacrylamide were synthesized and characterized and were tested on phagocytic cells. It was shown that these nanoparticles are actively captured by phagocytic cells and that they are not cytotoxic. The polymer nanoparticles loaded with cisplatin at different concentrations from 0.1 to 10 μg/mL yielded dose-dependent decrease in viability of chronic myelogenous leukemia and histiocytic lymphoma cells. The lowest percentage of viable cells was observed for lymphoma cells (22%). Taking into account the fact that our nanoparticles will act mainly on malignant phagocytic cells and do not affect healthy cells, they can thus potentially be used for the therapeutic treatment of tumor cells having phagocytic activity. The effect of nanosilver on cell viability was lower than the one of polymer/cisplatin composite. The data from the cytotoxic studies indicate that nanosilver induces toxicity in cells. However, when the copolymers were conjugated to both nanosilver and cisplatin, such a nanosystem displayed less cytotoxic effect compared to the conjugates of dextran-polyacrylamide and cisplatin.

Synthesis, Morphology, and Optical Properties of Au/CdS Hybrid Nanocomposites Stabilized by Branched Polymer Matrices

Metal/semiconductor Au/CdS nanocomposites were synthesized in the solution of branched D-g-PAA polymer. TEM and DLS of Au/CdS/D-g-PAA nanocomposites revealed complicated nanocomposite structure consisting of the Au nanoparticles NPs of 6 nm in size surrounded by small CdS NPs with size of 3 nm. These nanocomposites formed the aggregates-clusters with average size of 50–800 nm. Absorption spectra of Au/CdS nanocomposites consist of the bands of excitons in CdS NPs and surface plasmons in Au ones. The surface plasmon band of gold NPs is red shifted and broadened in Au/CdS/D-g-PAA nanocomposites comparing to the one of Au NPs in Au/D-g-PAA proving the fact of close location of CdS and Au NPs in the synthesized Au/CdS/D-g-PAA nanocomposites. The PL spectra of Au/CdS nanocomposites originate from the radiative transitions in excitons in CdS NPs. The 4-fold increase of intensity of free exciton PL is observed for CdS NPs in Au/CdS/D-g-PAA comparing to CdS ones in CdS/D-g-PAA that is due to PL enhancement by local field of surface plasmons of Au NPs. Also, the 12-fold decrease of intensity of localized exciton PL is observed for CdS NPs in Au/CdS/D-g-PAA comparing to CdS ones in CdS/D-g-PAA. Most probably, it is due to passivation of the surface of CdS NPs carried out by the Au ones.

A new triple system DNA-Nanosilver-Berberine for cancer therapy

The isoquinoline quaternary alkaloid Berberine possesses a variety of pharmacological properties that suggests its promising application for an anticancer delivery system design utilizing its ability to intercalate DNA. In the current work, we have investigated the effects of Berberine on the human T cell leukemia cell line in vitro. Fluorescent microscopy of leukemic cells revealed Berberine nuclear localization. The results showed that Berberine inhibited leukemic cell growth in a time- and dose-dependent manner, that was associated with reactive oxygen species production intensification and caspase 3/7 activity increase with followed apoptosis induction. Berberine was used as a toxic and phototoxic agent for triple system synthesis along with DNA as a carrier and nanosilver as a plasmonic accelerator of Berberine electronic transitions and high energy emission absorbent centers. The proposed method allows to obtain the complex of DNA with Berberine molecules and silver nanoparticles. The optical properties of free components as well as their various combinations, including the final triple system DNA-Nanosilver-Berberine, were investigated. Obtained results support the possibility to use the triple system DNA-Nanosilver-Berberine as an alternative therapeutic agent for cancer treatment.

The peculiarities of Raman spectra of carbon materials

A study of forbidden Raman line shapes of various carbon structures is presented. We have carried out epy experimental investigations and comparative analysis of spectra in the range of allowed E2g G-band of graphite (1500–1650 cm−1) and in the region of forbidden D-band (1310–1410 cm−1). Three doublets 1350–1375 cm−1, 1510–1540 cm−1, and 1590–1626 cm−1 have been observed under specific resonant situations. For sharp determination of these bands we applied a method of the spectra subtraction and the second derivatives spectra.

New hybrid composites for photodynamic therapy: synthesis, characterization and biological study

Photodynamic therapy is a procedure that uses a photosensitizing drug to apply light therapy selectively to target cancer treatment. This study is focused on a synthesis and characterization of a new hybrid nanocomposites based on the branched copolymers dextran–polyacrylamide in nonionic, D-g-PAA and anionic D-g-PAA(PE) form, with incorporated gold nanoparticles (AuNPs) and photosensitizer chlorin e6 (Ce6) simultaneously. Double polymer/AuNPs and trial polymer/AuNPs/Ce6 were studied by TEM, UV–visible, SOSG fluorescence. It was found the drastic difference for absorbance for trial nanosystems synthesized in nonionic and anionic polymers matrices. It was established that for the nanocomposite synthesised in anionic polymer matrix with the Ce6:Au mass ratio 1:10 generation of singlet oxygen (1O2) was quite close to that for free Ce6. The study of ability of this nanosystem to sensitize MT-4 cells to photodynamic damage has shown that the nanocomposite, that contained AuNPs during the synthesis of which HAuCl4:NaBH4 mass ratio was 1:2 showed higher photodynamic activity, than Ce6 itself. Nanosystem D70-g-PAA(PE)/AuNPs/Ce6 can be recommended to experiment in vivo.

Semiconducting and Optical Properties of Compact Graphene-Like Nanoparticles of Molybdenum Disulfide

The research in the influence of graphene-like 2H-MoS2 nanoparticle structure on the behavior electroresistivity and optical properties has shown that the conductivity of semiconductor type (n-type) in the compact samples correlates with the particle sizes, in particular the size of 17–53 nm, along the basal plane [100] at a constant number of S–Mo–S nanolayers (n = 6–8) in graphene-like 2H-MoS2 nanoparticles. The mechanism of conductivity is supposed to be hopping conduction with variable hopping length for 2D case. The results of Raman studies indicate a significant impact of anisotropy sizes of 2H-MoS2 nanoparticles in direction [110] under constant number of nanolayers of S–Mo(W)–S on the formation of the structure-sensitive optical properties and, accordingly, the characteristics of the semiconductor as a whole.

Nanostructured Dextran-Graft-Polyacrylamide Flocculants: Effect of Internal Molecular Structure on Flocculative Efficiency

Branched nanostructured copolymers dextran-g-polyacrylamide (D-g-PAA) in uncharged and anionic form were synthesized, characterized, and tested for flocculation in comparison with linear PAA. The polymers differed in the conformation of grafted polyacrylamide chains determining the molecular compactness. Kaolin clay dispersion with a high content (more than 60%) of particles less than 2 μm in size, which settle down with difficulty, was used as a model system. It was shown that branched copolymers exhibited high flocculation activity in noncharged and ionic forms. In contrast to linear polymers, not only the size of the macromolecule polymer flocculants but also their molecular nanostructure affected the parameters (sedimentation rate and degree of supernatant clarification) of the flocculation process. The degree of supernatant clarification for branched polymers at optimal flocculant concentrations was higher than for linear PAA. Branched and linear flocculants in anionic form were tested and compared with respect to flocculation for kaolin dispersion setting as well as for efficiency at removing Cu2+, Co2+, and Ni2+ ions during the flocculation process. Branched molecules were more efficient at trapping heavy metal ions than linear PAA. The ability to remove Ме2+ ions from clay dispersion was greatest for anionic branched copolymers.

Spectral Properties of Carbazole- and Phenothiazine-Containing Low-Molecular Compounds for Photonics

Aza-compounds derivatives such as carbazole and phenothiazine are intensively studied as potential components of organic electronics, particularly of OLEDs. The present paper deals with investigations of spectral properties of specific carbazole- and phenothiazine-containing low-molecular glass-forming compounds, i.e., 3-(9-carbazolyl)-9-ethylcarbazole, 3-(9-pheothiazinyl)-9-ethylphenothiazine, 3-(9-pheothiazinyl)-9-ethylcarbazole, and 3-(9-carbazolyl)-9-ethylphenothiazine in different aggregative states (solid samples and solutions) and at different temperatures (77° K, 293° K). The location of the first singlet and triplet energy levels of the investigated compounds has been estimated from the spectral data. The high probability of the intercombinatory transition to the triplet state for the solutions and solid samples of 3-(9-pheothiazinyl)-9-ethylphenothiazine, 3-(9-pheothiazinyl)-9-ethylcarbazole, and 3-(9-carbazolyl)-9-ethylphenothiazine has been stated.