1. Introduction

Since the end of the twentieth century, nanotechnologies have been gaining ground in various fields involving chemistry, biology, physics and medicine. In particular, under the name of nanomedicine, a great deal of research is now focusing on the future use of nanoparticles for clinical applications. Nanoparticles offer a number of attractive features for medical applications: (i) access to new properties linked to the nanometric scale (optical, magnetic, for example), (ii) multimodal character (the possibility of coupling several functionalities on the same object), (iii) modulable biodistribution through the addition of targeting species or optimization of size and surface properties enabling specific targeting of diseased areas, (iv) amplified signal with the possibility of bringing together several imaging or therapeutic agents within the same object. Nevertheless, despite these attractive...