properties of copper nanoparticles
Various physical, chemical and biological properties have been observed in copper nanoparticles (NPs) such as antimicrobial activity, specific drug transport, photoluminescence and anticancer activities. These properties are important to determine the potential biocompatibility of copper NPs with humans and animals.
Synthesis and characterization of copper nanoparticles are essential for understanding their effects on humans, animals and environment. A variety of characterization techniques are available, including X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy and magnetic measurements.
A TEM study of bare Cu NPs prepared by a solution process revealed that the interatomic distance of the Cu atoms is constant up to the outermost surface, which is an interatomic distance of 0.25 nm in the [1
Non-oxidized bare Cu NPs are stable in air after 15 and 31 days. The energy-loss near-edge structure of metallic Cu (Supplementary Figs. a, b and c) displayed by bare Cu NPs over time is closely akin to that of all of the displayed non-oxidized Cu NPs.
In addition, these non-oxidized bare Cu NPs were found to be stable in deionized water for 60 min, without any additional post-treatments or surface passivation processes required. This result suggests that the direct transfer of excess electrons to Cu NPs is sufficient to ensure their oxidation resistance in the mass-produced bare form, as previously observed for oxygen-adsorbed silver NPs.