Electron microscopy of nanoparticles in cells

Biomedical application of nanoparticles (NPs) is an emerging discipline within which electron microscopy (EM) is an essential tool for identifying intracellular location of NPs. NP dispersion, dissolution and dose internalised by cells and tissues can all be monitored and quantified by EM, but this will only be accurate with appropriate sample preparation. Preparation of cellular material for EM must consider the resolution of cellular ultrastructure while avoiding significant alteration or loss of target NPs. There are a wide range of EM imaging modes now available that have the pre-requisite spatial resolution and sensitivity to measure and quantify the position and number of NPs in a biological matrix. In addition, quantification of NP composition and the ionic content within intracellular compartments is possible by analytical EM. These techniques involve both scanning and transmission EM and cross the traditional boundaries between EM for the biological and physical scientists. This chapter aims to summarise the use of EM for the analysis of NPs in cells and tissues and will briefly discuss correlation with live cell imaging.