BRIC Seminar Series October 2017 – Nicolas Tsapis, PhD

Nicolas Tsapis, Ph.D.

Institute Galien Paris-Sud, CRNS, Universite Paris-Sud, Universite Paris-Saclay

Capsules of Perfluorocarbons as Theranostic Agents

Abstract

The need to detect cancer at its early stages, as well as, to deliver chemotherapy to targeted site motivates many researchers to build theranostic platforms which combine diagnostic and therapy. Among imaging modalities, ultrasonography and MRI are widely available, non invasive and complement each other. Both techniques often require the use of contrast agents.

We have developed nanocapsules of perfluorocarbons as dual contrast agent for both imaging modalities. The soft, amorphous polymer shell provides echogenicity, while the high-density perfluorinated liquid core allows detection by ¹⁹ F MRI. We have used mainly a shell of poly(lactide-co-glycolide) (PLGA) since this polymer is biodegradable, biocompatible and can be loaded with drugs. These capsules were shown to be efficient in vitro as contrast agents for both ¹⁹ F MRI and ultrasonography¹. In addition, for in vivo applications a poly(ethyleneglycol) (PEG) coating promotes stability and prolonged circulation. Being stealth, nanocapsule can accumulate passively into implanted tumors by the EPR effect. We will present nanocapsule formulation and characterization, and will show promising in vivo results obtained for both ultrasonography and ¹⁹ F MRI². The accumulation by EPR effect favors the efficacy of a chemotherapeutic agent co-encapsulated, proving the feasibility of the theranostic approach. The different parameters one can play with to modulate the detection of these contrast agents will be presented. The limitations of these nanoparticles and the strategies to overcome them will be reviewed.