Imaging of Nanopollutants at Sub-cellular Resolution by Nanoscale Secondary Ion Mass Spectrometry

Nanoscale secondary ion mass spectrometry (NanoSIMS) is an analytical imaging technique dedicated to the mapping of the elemental composition on the surface of a solid sample. The distinguishing features of this techniques make it especially convenient for the analysis of nanopollutants in the environment: the possibility to focus its scanning ion beam into a spot size equal or lower than 50 nm makes it adequate to investigate nano-sized objects, and the high sensitivity of its mass spectrometer enables the analysis of pollutants at trace concentrations. The main strength of the technique is the capacity for the localisation of these nanopollutants, including their subcellular distribution, down to an organelle level. Adequate sample preparation strategies permit the analysis of nanopollutants in a variety of media such as soils, food and organisms, including in vivo and in vitro. To date, a limited number of studies have used NanoSIMS in the field of environmental science, with most works focusing on metal nanoparticles, and especially the imaging of silver nanoparticles in aquatic organisms. Yet, the NanoSIMS applications are expected to continue growing in the following years with further developments in the instrument and novel fields.