Fig. 1. Based on a recent review by Anselmo and Mitragotri (2019) listing 89 NP formulations that are currently approved for use in the clinic or undergoing clinical trials, 75% of these regimens are indicated for cancer treatment (including gene therapy) or diagnosis, of which 90% are composed of organic materials such as liposomes, polymers and micelles.7 Six of the inorganic NP formulations that are clinically approved are used for imaging, while only one (NU-0129) functions as a direct therapeutic. As of 2019, NU-0129, consisting of Au NPs surface-covered with nucleic acids, is being tested in phase I clinical trials for the treatment of glioblastoma. The indirect-acting NPs exert their anticancer activity through radiation or thermal ablation by an external source.
