Light-triggered redox activity of GdYVO4:Eu3+ nanoparticles.

Light-triggered redox activity of small (d = 2 nm) GdYVO4:Eu3+ nanoparticles (NPs) in aqueous solutions and lipid suspensions is reported. It has been revealed that depending on pre-treatment conditions (exposure to UV light or storage in the dark) the same NPs exhibit pro- or anti-oxidant properties. Pro-/anti-oxidant activity in aqueous solutions was evaluated by UV-vis spectroscopy using probe molecules for hydroxyl radicals (·OH) and superoxide anions (O2•-). Lipid oxidation under the effect of NPs has been also analyzed. Multi-functional GdYVO4:Eu3+ NPs are assumed to be a new theranostic agent in cancer therapy, which exhibit fluorescent properties, triggered redox activity and drug-carrier ability.

Excimer Emission of Acridine Orange Adsorbed on Gadolinium-Yttrium Orthovanadate Nanoparticles.

Studying the complexes of inorganic nanoparticles - organic dye molecules is of great importance for their theranostics application. In this paper, we report gadolinium-yttrium orthovanadate nanoparticles (VNPs) - Acridine Orange (AO) complex formation in water solutions. To study the interactions between VNPs and AO, the methods of steady-state and time-resolved spectroscopy were used. It was shown that in aqueous solutions containing VNPs, AO aggregation takes place with a sandwich-like stacking of AO molecules in the near-surface layer of VNPs. The VNPs-AO complex formation causes significant changes in the AO fluorescence spectrum, namely, the appearance of a new broad, structureless band in the long-wavelength spectral edge, which was not observed in AO spectrum in a pure water solution. By analyzing of the absorption, fluorescence excitation spectra and fluorescence decay, the static excimer origin of the long-wavelength fluorescence band has been established.

[THE INFLUENCE OF NANODISPERSE CERIUM DIOXIDE ON ONTOGENETIC CHANGES OF ANTIOXIDANT SYSTEM IN THE MUCOSA OF THE STOMACH AND COLON IN RATS].

It was established that with age the content of lipid peroxidation products increased in the mucosa of the stomach: Diene conjugates by 30%, products which react to thiobarbituric acid by 285% and Schif bases by 181%. Nanodisperse cerium dioxide (NCD) reduced the content of lipid peroxidation in the gastric mucosa in old rats: Diene conjugates by 43 %, products which react to thiobarbituric acid by 51% and Schif bases by 44% relative to the control group of rats given age. Similarly, it was established that the content of Diene conjugates increased by 40%, products which react to thiobarbituric acid by 114% and Schif bases by 132% in the mucosa of the colon of old rats. NDC significant reduced the content of products which react to thiobarbituric acid by 69% and Schyf basics by 132%. In the stomach superoxide dismutase (by 43%) and catalase activity (by 24%) decreases with age, while in the colon superoxide dismutase activity increases (by 43%). In the colon NCD significant decreased superoxide dismutase (by 34%) and catalase activity (by 21%) relative to controls. Thus, the NDC restores lipid peroxidation in the gastric mucosa and colon, in which develops oxidative stress with age.

[FUNCTIONAL ACTIVITY OF EHRLICH CARCINOMA CELLS AFTER TREATMENT WITH HYBRID NANOCOMPLEXES CONTAINING ORTHOVANADATES OF RARE-EARTH ELEMENTS, CHOLESTEROL AND LUMINESCENT DYE].

Tumor development is the consequence of expanding the population of low differentiated cells with unlimited self-maintenance potential, i.e. cancer stem cells (CSCs). Application of new forms of nanocomposites capable of binding to CSCs and inducing the tumor destruction is perspective direction for treating this pathology. There have been developed the methods of obtaining hybrid nanocomplexes containing rare-earth orthovanadates GdYVO4:Eu³âº, cholesterol and luminescent dye Dil. By immune fluorescence method using monoclonal antibodies to CD44, CD24, CD117 and Sca-1 markers there has been established the change in the ratio of tumor progenitors of various differentiation levels in a general pool of Ehrlich carcinoma (EC) after treatment with hybrid nanocomplexes. Essential reduction in the concentration of the most tumorogenic CD44high cells with simultaneous rise in the number of CD117⁺-cells resulted in an increased index of CD44high/CD117⁺ ratio. It has been demonstrated that application of hybrid nanocomplexes suppressed the tumor growth almost by 80%. The value of cooperative interactions of the cells with different phenotype signs in tumor sites has been proved. The index of CD44high/CD117⁺ ratio can be used as one of diagnostic and prognostic parameters of development and inactivation rate of tumor process when using different types of anti-tumor therapy.

Comparative study of dye-loaded liposome accumulation in sensitive and resistant human breast cancer cells.

UNLABELLED: The aim of this research is to study the dynamics and efficiency of liposome accumulation in sensitive and resistant human breast cancer cells. METHODS: Methods of fluorescence microscopy, fluorescence microspectroscopy and MTT-test have been used. RESULTS: The liposome-to-cell interaction and dye cellular uptake in sensitive, cisplatin-resistant and doxorubicin-resistant MCF-7 human breast cancer cells have been analyzed using time changes in both fluorescence resonance energy transfer signal from the donor probe DiO to the acceptor one DiI preloaded in liposomes and cell image brightness. CONCLUSION: Obtained results show that resistant cells accumulate dye-loaded liposomes more effectively and reveal more effective dye molecule cellular uptake.

Specificity of cyanine dye L-21 aggregation in solutions with nucleic acids.

Optical spectroscopy experiments were used to study the features of cyanine dye 3,3'-dimethyl-9-(2-thienyl)-thiacarbocyanine iodide (L-21) aggregation in binary solutions DMF:Tris-HCl buffer (pH = 8) containing nucleic acids (DNA or RNA). The appearance of absorption and luminescence bands associated with J-aggregates and dimers that are formed within the minor groove of DNA has been observed. The model of L-21 J-aggregate structure is proposed. It has been found that dimers are the building blocks of L-21 J-aggregates. Disorientation in dimers caused by the minor groove curvature is reason of observation of Davydov splitting in absorption spectrum of L-21 J-aggregates. In the solution containing DNA the absorption and luminescence bands of L-21 J-aggregates exhibit the specific properties that allows the dye L-21 to be used as a fluorescent probe for DNA detection.