ABSTRACT
Nanomaterials occurring as single particles within the nanosize range are small enough to diffuse in living tissues of the organisms and to penetrate into cells. The synthesis of articial nanomaterials appeared reproducible enough at the end of the 1960s and beginning of the 1970s (Bangham et al., 1965, see for references Daniel, J.C. 2003). They appeared suitable to serve as drug carriers (Gregoriadis, 1976; Kreuter and Speiser, 1976; Kreuter, 2007) and attracted an immediate interest to realize the “magic bullet,” a concept imagined by Paul Ehrlich, winner of the Nobel Prize in Physiology and Medicine in 1908. The rationale behind this idea was to develop a method of drug delivery by reducing the severe side effects of the drugs used in chemotherapies of cancer and infections, thanks to a better targeting of the drug to diseased tissues. The early stages of nanomedicine development have considered liposomal formulations of chemotherapeutic agents during the 1970s (Gregoriadis, 1976; Juliano, 1976; Gregoriadis et al., 1974). Since then, the eld of nanomedicine has expanded considerably. Many types of nanomaterials have been proposed to serve as drug carriers for not only small molecules but also for biomacromolecules, including therapeutic peptides, proteins, and all kinds of nucleic acids that can be used to control the expression of a specic gene and can be applied to gene therapy. Proofs of concept for the delivery of most of these molecules, considering different modalities for their administration, have now been provided (Couvreur and Vauthier, 2006; Farokhzad and Langer, 2009; Etheridge et al., 2013; Lehner et al., 2013). Besides applications that overcome drug delivery challenges, several types of interesting nanomaterials were found to improve the performance of imaging techniques used in diagnostics (Liu et al., 2011). Theragnostic, a new nanomedicine eld, uses a combination of drug delivery and diagnostics in a single nanomaterial (Mura and Couvreur, 2012). Finally, several types of nanomaterials can be used to potentiate the effect of radiotherapy (Bakht et al., 2012). They are used to focus the effects of radiations after implantation within tumors that enhances the efcacy of the radiotherapy. Several of these nanomaterials are bringing hope toward the development of noninvasive methods for the ablation of tumors with the ambition to displace classical surgery.
