ABSTRACT
Copper (I) oxide (cuprite) is a material widely used nowadays, and its versatility is further amplified when it is brought to the nanometric size. Among the possible applications of this nanomaterial, one of the most interesting is that in the medical field. This paper presents a cuprite nanopowder study with the aim of employing it in medical applications. With regards to the environmental context, the synthesis used is related to green chemistry since the technique (out-of-phase pulsed electrochemistry) uses few chemical products via electricity consumption and soft conditions of temperature and pressure. After different physico-chemical characterizations, the nanopowder was tested on the Candida albicans to determine its fungicide activity and on human blood to estimate its hemocompatibility. The results show that 2 mg of this nanopowder diluted in 30 µL Sabouraud broth was able to react with Candida albicans. The hemocompatibility tests indicate that for 25 to 100 µg/mL of nanopowder in an aqueous medium, the powder was not toxic for human blood (no hemolysis nor platelet aggregation) but promoted blood coagulation. It appears, therefore, as a potential candidate for the functionalization of matrices for medical applications (wound dressing or operating field, for example).
ABSTRACT
Cu-Ag core-shell nanopowders have been prepared by ultrasound-assisted electrochemistry followed by a displacement reaction. The composition of the particles has been determined by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). The XRD patterns versus time displacement show that higher are the silver peaks intensities, weaker are the copper ones. That exhibits the progressive recovering of copper by silver. EDX results and quartz crystal microbalance results indicate that various reaction mechanisms are implied in this process. Transmission electron microscopy (TEM) points out variable nanometric diameter grain and some small agglomerates. Elemental mapping obtained by electron energy-loss spectroscopy (EELS) underlines the core-shell structure.
ABSTRACT
A new flowmetric method of the power dissipated by an ultrasound generator in an aqueous medium has been developed in previous works and described in a preceding paper [V. Mancier, D. Leclercq, Ultrasonics Sonochemistry 14 (2007) 99-106]. The works presented here are an enlargement of this method to a high viscosity liquid (glycerol) for which the classical calorimetric measurements are rather difficult. As expected, it is shown that the dissipated power increases with the medium viscosity. It was also found that this flowmetric method gives good results for various quantities of liquid and positioning of the sonotrode in the tank. Moreover, the important variation of viscosity due to the heating of the liquid during experiments does not disturb flow measurements.
Subject(s)
Rheology/methods , Ultrasonics , Algorithms , Calorimetry , Glycerol/chemistry , Hot Temperature , Thermodynamics , Titanium , ViscosityABSTRACT
Cu(2)O nanopowders have been prepared by ultrasound-assisted electrochemistry with a potentiostatic set-up. Their composition has been determined by X-ray diffraction and energy dispersive X-ray spectroscopy. Transmission electron microscopy and centrifugation analyses indicate that the nanopowders consist of agglomerates of variable nanometric diameter grain. Most of particles have a diameter of 8 nm whatever the electrodeposition potential. The influence of the parameters of electrochemical and ultrasonic pulses on the particle diameter was also studied. The specific surface areas determined by Brunauer-Emmet-Teller (BET) model are very high with a value close to 2000 m(2)g(-1).
Subject(s)
Copper/chemistry , Electrochemistry/instrumentation , Metal Nanoparticles/chemistry , Electrochemistry/methods , Electrolytes , Equipment Design , Hydrogen-Ion Concentration , Microscopy, Electron, Transmission , Models, Chemical , Powders , Semiconductors , Temperature , X-Ray DiffractionABSTRACT
Two new determination methods of the power dissipated in an aqueous medium by an ultrasound generator were developed. They are based on the use of a heat flow sensor inserted between a tank and a heat sink that allows to measure the power directly coming through the sensor. To be exploitable, the first method requires waiting for stationary flow. On the other hand, the second, extrapolated from the first one, makes it possible to determine the dissipated power in only five minutes. Finally, the results obtained with the flowmetric method are compared to the classical calorimetric ones.
