Synthesis, Radiolabelling and In Vitro Imaging of Multifunctional Nanoceramics.

Molecular imaging has become a powerful technique in preclinical and clinical research aiming towards the diagnosis of many diseases. In this work, we address the synthetic challenges in achieving lab-scale, batch-to-batch reproducible copper-64- and gallium-68-radiolabelled metal nanoparticles (MNPs) for cellular imaging purposes. Composite NPs incorporating magnetic iron oxide cores with luminescent quantum dots were simultaneously encapsulated within a thin silica shell, yielding water-dispersible, biocompatible and luminescent NPs. Scalable surface modification protocols to attach the radioisotopes 64Cu (t1/2=12.7 h) and 68Ga (t1/2=68 min) in high yields are reported, and are compatible with the time frame of radiolabelling. Confocal and fluorescence lifetime imaging studies confirm the uptake of the encapsulated imaging agents and their cytoplasmic localisation in prostate cancer (PC-3) cells. Cellular viability assays show that the biocompatibility of the system is improved when the fluorophores are encapsulated within a silica shell. The functional and biocompatible SiO2 matrix represents an ideal platform for the incorporation of 64Cu and 68Ga radioisotopes with high radiolabelling incorporation.

Copper-catalyzed one-pot synthesis of N-aryl oxazolidinones from amino alcohol carbamates.

An efficient sequential intramolecular cyclization of amino alcohol carbamates followed by Cu-catalyzed cross-coupling with aryl iodides under mild conditions has been developed. The reaction occurred in good yields and tolerated aryl iodides containing functionalities such as nitriles, ketones, ethers, and halogens. Heteroaryl iodides and substituted amino alcohol carbamates were also well tolerated.

Comparative assessment of technologies for extraction of artemisinin.

This paper describes results of a multiobjective comparative assessment of several established and emerging technologies for extraction of a natural antimalarial substance, artemisinin. Extractions by hexane, supercritical carbon dioxide, hydrofluorocarbon HFC-134a, ionic liquids, and ethanol were considered. Hexane extraction is an established technology and appears to be the most cost-effective. However, it is characterized by lower rates and efficiency of extraction than all other considered techniques and is also worse in terms of safety and environmental impact. Similarly, EtOH extraction was found to be worse than hexane in all assessment parameters. The new technologies (scCO2, HFC, and ILs) are based on nonflammable solvents and are characterized by faster extraction cycles and more complete extraction of the useful substances and enable continuous extraction processes with reduced solvent inventory. Ionic liquid and HFC-134a technologies show considerable promise and should be able to compete with hexane extraction in terms of cost-effectiveness following due process optimization. New technologies are also considerably safer (no risk of explosions, low toxicity) and greener (having a lower environmental impact in use, potential for biodegradability after use). The methodology of comparative assessment of established and emerging technologies is discussed.

Reversible storage of molecular hydrogen by sorption into multilayered TiO2 nanotubes.

The sorption of hydrogen between the layers of the multilayered wall of nanotubular TiO2 was studied in the temperature range of -195 to 200 degrees C and at pressures of 0 to 6 bar. Hydrogen can intercalate between layers in the walls of TiO2 nanotubes forming host-guest compounds TiO2 x xH2, where x < or = 1.5 and decreases at higher temperatures. The rate of hydrogen incorporation increases with temperature and the characteristic time for hydrogen sorption in TiO2 nanotubes is several hours at 100 degrees C. The rate of intercalate formation is limited by the diffusion of molecular hydrogen inside the multilayered walls of the TiO2 nanotube. 1H NMR-MAS and XRD data confirm the incorporation of hydrogen between the layers in the walls of TiO2 nanotubes. The nature and possible applications of the observed intercalates are considered.