SEM X-ray microanalysis of nanoparticles present in tissue or cultured cell thin sections

Energy Dispersive X-ray (EDX) microanalysis is a technique used for identification of the elemental composition of a specimen. The detection of nanoparticles in tissue is a common problem of biodistribution and toxicity studies. High-resolution transmission electron microscopy (TEM) can be employed to detect nanoparticles based on morphology; however, TEM alone cannot conclusively identify nanoparticles. Indeed, micrographs are often ambiguous due to particle aggregation, contamination, or morphology change after cellular uptake. EDX can be used to confirm the composition and distribution of the nanoparticles through spectrum and elemental mapping. This protocol outlines the procedures for compositional identification of nanoparticles using an EDX spectrometer incorporated into a scanning electron microscopy (SEM) system. This protocol outlines sample preparation, EDX spectrum acquisition, elemental peak analysis and spectral mapping acquisition.