Size-Controlled Transformation of Cu2O into Zero Valent Copper within the Matrix of Anion Exchangers via Green Chemical Reduction.

Composite materials containing zero valent copper (ZVC) dispersed in the matrix of two commercially available strongly basic anion exchangers with a macroreticular (Amberlite IRA 900Cl) and gel-like (Amberlite IRA 402OH) structure were obtained. Cu0 particles appeared in the resin phase as the product of the reduction of the precursor, i.e., copper oxide(I) particles previously deposited in the two supporting materials. As a result of a one-step transformation of preformed Cu2O particles as templates conducted using green reductant ascorbic acid and under mild conditions, macroporous and gel-type hybrid products containing ZVC were obtained with a total copper content of 7.7 and 5.3 wt%, respectively. X-ray diffraction and FTIR spectroscopy confirmed the successful transformation of the starting oxide particles into a metallic deposit. A scanning electron microscopy study showed that the morphology of the deposit is mainly influenced by the type of matrix exchanger. In turn, the drying steps were crucial to its porosity and mechanical resistance. Because both the shape and size of copper particles and the internal structure of the supporting solid materials can have a decisive impact on the potential applications of the obtained materials, the results presented here reveal a great possibility for the design and synthesis of functional nanocrystalline solids.

In vivo study on the biodistribution of silica particles in the bodies of rats.

BACKGROUND: Biodegradable carrier materials with nontoxic degradation products are very valuable for delivering drugs and biologically active molecules. Many organic systems (such as liposomes, micelles and polymeric nanoparticles) and inorganic systems (metal oxides and silica) have been researched for delivering active substances to organs. Silica seems to be one of the most interesting and promising materials. OBJECTIVES: The aim of this study was to investigate the SiO2 elimination process from rats' organisms and to ascertain the distribution and prospective accumulation sites of the silica particles. MATERIAL AND METHODS: A suspension of silica particles (Ø 150 nm) in 0.9% NaCl solution was introduced into rats' circulatory system. The degradation of these particles over time and their accumulation in the heart, lungs, kidneys and liver were observed. RESULTS: It was found that 36% of the introduced silica particles were excreted with urine after four days. The remaining particles were accumulated in the kidneys and lungs, probably in the lung air sacs and kidney glomerulus. CONCLUSIONS: Silica seems to be promising carrier material. Silica particles dissolve in the rat's body and are eliminated in urine.

The effect of substrate roughness on the surface structure of TiO(2), SiO(2), and doped thin films prepared by the sol-gel method.

Pure and calcium-doped silica and titanium dioxide thin films were prepared by the sol-gel method. Two different metallic substrates, i.e. stainless steel (316L) and titanium alloy (Ti6Al4V), were used for thin film deposition. Physicochemical properties and roughness of the thin films derived were investigated using the Raman spectroscopy, X-ray diffraction analysis, scanning electron microscopy and Taylor-Hobson's surface analyser. It is suggested that the synthesized coatings display physicochemical and surface properties suitable for materials used for implant.