Spectroscopic and nanoscale characterization of blue-coloured smithsonite (ZnCO3) from Lavrion historical mines (Greece)

Spectroscopic and microscopic (particularly HRTEM) techniques were used to investigate the origin of the colour of natural blue Zn-carbonate (smithsonite). Blue smithsonite is rich in copper, but substitution of zinc cations by copper cations, as proposed in the past for the origin of the colour, is questionable considering the absence of anhydrous divalent copper carbonates in nature. In this work, optical microscopy, SEM-EDS, XRD and laser micro-Raman could not resolve distinct phases either than Zn-carbonate, while NIR spectra excluded known chromophore Cu-hydroxycarbonate minerals. HRTEM studies however could clearly resolve nano-sized (3-7 nm) Cu-rich inclusions (specifically Si/Ca/Cu/As-rich inclusions of at least one phase), which are organised in bands with no topotaxial relation to bulk smithsonite. Electron-beam sensitivity of the samples, even at low electron current densities, did not allow the exact identification of the inclusions. However, it can be safely suggested, for the first time in the literature, that they are the cause of the blue colour in smithsonite

Magnetic Nanoparticles for Diagnosis and Medical Therapy

Magnetic nanoparticles (MNPs) reveal promising opportunities for biomedical applications, potentially allowing minimally invasive diagnosis and therapeutic usage at several levels of human body organization (cells, tissue and organs). An increasingly broad collection of MNPs has been recently developed not only at the research level but also in some specific cases for medical applications. Superparamagnetic iron oxide (SPIO) nanoparticles are commonly used in clinical practice as contrast agents for magnetic resonance imaging (MRI) of liver and angiography. Carbon nanotubes (CNTs) are another type of nanomaterials with great potential for biomedical applications. Filled with ferromagnetic materials, an ensemble of aligned CNTs displays a highly non-linear, anisotropic and hysteretic magnetization behaviour due to their extremely high aspect ratio (length/diameter >100). The intrinsic properties of such ferromagnetic nanoparticles can potentially improve diagnosis and therapy of numerous diseases. Combining tailored biocompatible ferromagnetic nanomaterials with dedicated detection technology can provide a new approach leading to the exciting perspective of accurate medical imaging and medical therapy (magnetic hyperthermia, targeted drug delivery, etc.) at the cellular level. Elongated Fe-filled CNTs (Fe-CNTs) are foreseen as potential nanotools leading to minimally invasive, highly sensitive, and cost effective novel investigation routes for complete human body systems