Intracellular Investigation of Nanoparticles for Drug Delivery

In the last decades, nanoparticles have shown an outstanding potential as drug delivery systems to increase the efficiency of conventional chemotherapy. Unlike drug molecules, drug-carrying nanoparticles can be engineered to increase drug blood circulation time, to target cancer cells, to defeat intracellular barriers, and to release the drug intracellularly. This multi-functionality can drastically increase chemotherapy efficiency and decrease the severe side effect of chemotherapy. To this purpose, a myriad of different multifunctional nanomaterials has been developed. Most of them have, however, not yet reached clinical trials. For boosting their clinical translation, the understanding of nanoparticle behavior and action in cells is crucial. Fluorescence microscopy can be applied to elucidate nanoparticle interactions with cells, their internalization rate, intracellular fate and location, controlled drug release, and degradation. This chapter is dedicated to explaining each important aspect of a nanoparticle-based drug delivery system to be investigated and how experimentally this investigation can be done by reporting some examples.