(S)TEM structural and compositional nanoanalyses of chemically synthesized glutathione-shelled nanoparticles

Abstract

This work is focused on the characterization by Transmission and Scanning Transmission Electron Microscopy related techniques of core-shell nanoparticles synthesized via chemical methods. Different semiconducting, pure metallic or oxide materials have been utilized as the core (CdTe, Au, Fe 3 O 4 , or Fe 3 O 4 covered with Au) of the nanoparticle, while they have been, in all cases, functionalized by a thin amorphous glutathione layer, with the goal of using the NPs in biomedical applications such as biomarkers, and computerized tomography and image magnetic resonance contrast agents. The results show that it is possible to visualize the glutathione layer using spectroscopic and imaging techniques, associated to electron microscopy (such as energy dispersive X-ray spectroscopy and high-resolution transmission electron microscopy images), that this layer is present at the surfaces of all observed nanoparticles, and that it is no thicker than a few nanometers. Electron microscopy also revealed that the nanoparticles core are crystalline and, in average, around 5-nm-size