Composite functional nanomaterials assembled via electrostatic interactions of inorganic surfaces and organic molecules

The surface of some minerals when in contact with aqueous environments is observed to develop a layer of electric charges which allows for the formation of stable adducts with foreign chemical species of opposite charge. Due to the increment of the surface-to-volume ratio, this effect is enhanced when the mineral is in the form of nanoparticle. Here, we show the peculiar characteristics of synthetic layered chrysotile mineral nanotubes, which have been used to ionically anchor fluorescent organic dyes and properly modified magnetic nanoparticles, conferring useful functionalities to the so-obtained adduct. Indeed, such composite nanomaterial displays optical and chemical sensitiveness to pH changes in the acidic range and allows for contrast enhancement in magnetic resonance imaging. In combination with a high overall biocompatibility, such functionalized nanotubes are becoming promising platforms for the development of low-impact multimodal diagnostic and therapeutic tools.