ИСТИНА

In recent time, metallic nanoclusters attract a great attention because of their outstanding physical properties. Gold nanoclusters (GNCs) stand out from others due to their perfect stability and biocompatibility. Therefore, GNCs are widely used in biosensing and bioimaging. In this study, we tried to use GNCs for hydroperoxide sensing. It is well known, that enhanced level of H2O2 in human cells is one of the diagnostic characters of oncogenesis. Thus, selective sensing of H2O2 can have great significance in cancer diagnostics and therapy. Such selectivity can be provided by using remarkably selective peroxyoxalate chemilumenescent reaction (PO-reaction) between aromatic oxalates and H2O2 in the presence of activators (commonly, polyaromatic compounds).Recently, it has been demonstratedthat glutathione-capped GNCs can serve as activators of PO-reaction in water-ethanol mixtures. However, it is known that oxalates are unstable in water solution. Therefore, both oxalate and activator should be placed into hydrophobic surroundings. We synthesized glutathione-capped GNCs according to previously published protocol and confirmed size distribution and structure of the GNCs by electrophoresis, fluorescent spectroscopy, spectrophotometry, RFA and 1H-NMR spectroscopy. We have also demonstrated extremely high catalytic activity of GNCs in model reaction between p-nitropenol and NaBH4. Obtained clusters possessed high solubility in water and were not soluble in organic solvents. To use these GNCs in PO-reaction, we hydrophobized them by modification of carboxylic group of glutathione by octylamine, using carbodiimide method. Successes of modification was confirmed by 1H-NMR spectroscopy. Modified clusters had good solubility in methanol and DMF. Emulsion of pluronic L61 was used as a hydrophobic medium for PO-reaction. We demonstrated for the first time that the hydrophobized glutathione-capped GNCs could serve as activator of PO-reaction in polymeric emulsions.