PVP-stabilized tungsten oxide nanoparticles: pH sensitive anti-cancer platform with high cytotoxicity.

Photochromic tungsten oxide (WO3) nanoparticles stabilized by polyvinylpyrrolidone (PVP) were synthesized to evaluate their potential for biomedical applications. PVP-stabilized tungsten oxide nanoparticles demonstrated a highly selective cytotoxic effect on normal and cancer cells in vitro. WO3 nanoparticles were found to induce substantial cell death in osteosarcoma cells (MNNG/HOS cell line) with a half-maximal inhibitory concentration (IC50) of 5 mg/mL, while producing no, or only minor, toxicity in healthy human mesenchymal stem cells (hMSc). WO3 nanoparticles induced intracellular oxidative stress, which led to apoptosis type cell death. The selective anti-cancer effects of WO3 nanoparticles are due to the pH sensitivity of tungsten oxide and its capability of reactive oxygen species (ROS) generation, which is expressed in the modulation of genes involved in reactive oxygen species metabolism, mitochondrial dysfunction, and apoptosis.

Cerium oxide nanoparticles stimulate proliferation of primary mouse embryonic fibroblasts in vitro.

The increasing application of cell therapy technologies in the treatment of various diseases requires the development of new effective methods for culturing primary cells. The major limitation for the efficient use of autologous cell material is the low rate of cell proliferation. Successful cell therapy requires sufficient amounts of cell material over a short period of time with the preservation of their differentiation and proliferative potential. In this regard, the development of novel, highly efficient stimulators of proliferative activity in stem cells is a truly urgent task. In this paper we have demonstrated that citrate-stabilized cerium oxide nanoparticles (nanoceria) enhance the proliferative activity of primary mouse embryonic fibroblasts in vitro. Cerium oxide nanoparticles stimulate cell proliferation in a wide range of concentrations (10(-3)М-10(-9)M) through reduction of intracellular levels of reactive oxygen species (ROS) during the lag phase of cell growth and by modulating the expression level of the major antioxidant enzymes. We found the optimal concentration of nanoceria, which provides the greatest acceleration of cell proliferation in vitro, while maintaining the levels of intracellular ROS and mRNA of antioxidant enzymes in the physiological range. Our results confirm that nanocrystalline ceria can be considered as a basis for effective and inexpensive supplements in cell culturing.

Facile fabrication of luminescent organic dots by thermolysis of citric acid in urea melt, and their use for cell staining and polyelectrolyte microcapsule labelling.

Luminescent organic dots (O-dots) were synthesized via a one-pot, solvent-free thermolysis of citric acid in urea melt. The influence of the ratio of the precursors and the duration of the process on the properties of the O-dots was established and a mechanism of their formation was hypothesized. The multicolour luminescence tunability and toxicity of synthesized O-dots were extensively studied. The possible applications of O-dots for alive/fixed cell staining and labelling of layer-by-layer polyelectrolyte microcapsules were evaluated.

Formation of long-lived reactive species of blood serum proteins by the action of heat.

It has been previously established that heat induces the formation of reactive oxygen species (ROS) in aqueous solutions. In biological systems, ROS cause oxidative damage predominantly to proteins due to their abundance and sensitivity to oxidation. Proteins oxidized by the action of X-rays represent long-lived reactive species, which trigger the secondary generation of ROS (Bruskov et al. (2012) [25]). Here we studied the possibility of formation of long-lived species of the blood serum proteins bovine serum albumin and bovine gamma-globulin in air-saturated solutions under the action of heat. It is shown that heat induces the generation of long-lived protein species, which in turn generate ROS ((1)О2, (·)O2(-), (·)OН, and H2O2). The formation of the long-lived reactive species of BSA and BGG with a half-life of about 4h induced by moderate hyperthermia was revealed using the chemiluminescence of protein solutions. It was found that long-lived reactive species of BSA and BGG cause prolonged generation of H2O2. The results obtained suggest that H2O2 produced by proteins after heating represents a messenger in signaling pathways and produces therapeutic effects in living organisms.