Localization and Number of Au Nanoparticles in Optically Indexed Cells by FIB Tomography

Abstract

Gold nanoparticles (GNPs) are gaining importance as therapeutic chemical delivery vehicles, medical diagnostic tools, and phototherapeutic and contrast enhancement agents. GNPs are uniquely suited for these biological uses because of their chemical stability, novel optical properties, and broad potential for functionalization. Additionally, each of these beneficial properties is further enhanced by the ability to manufacture GNPs in an almost endless combination of sizes and shapes. This versatility has allowed researchers to access and modify biological processes inside of a large variety of cells [1] and the observation of innocuous uptake of citrate stabilized GNPs [2]. To describe the effect of GNPs, characterization of affected cells and tissues is required from the macroscopic to nanoscopic level. In particular, the location of cells in the tissue or culture of interest and then the mapping of the number and spatial distribution of the GNPs inside of those cells is required, and frequently requires multiple imaging techniques [3]. We achieve the large scale mapping of mammalian stem cells using reflection optical microscopy and then explore the location and number of the nanoparticles inside these cells after exposure to 60 nm GNPs using focused ion beam – scanning electron (FIB-SEM) based tomography.