Magnetic nanoparticles encapsulated into biodegradable microparticles steered with an upgraded magnetic resonance imaging system for tumor chemoembolization.

Abstract

In this work, therapeutic magnetic micro carriers (TMMC) guided in real time by a magnetic resonance imaging (MRI) system are proposed as a mean to improve drug delivery to tumor sites. MRI steering constraints and physiological parameters for the chemoembolization of liver tumors were taken into account to design magnetic iron-cobalt nanoparticles encapsulated into biodegradable poly(d,l-lactic-co-glycolic acid) (PLGA) microparticles with the appropriate saturation magnetization (M(s)). FeCo nanoparticles displayed a diameter of 182nm and an M(s) of 209 emicrog(-1). They were coated with a multilayered graphite shell to minimize the reduction of M(s) during the encapsulation steps. FeCo-PLGA microparticles, with a mean diameter of 58 microm and an M(s) of 61emicrog(-1), were steered in a phantom mimicking the hepatic artery and its bifurcation, with a flow in the same order of magnitude as that of the hepatic artery flow. The steering efficiency, defined as the amount of FeCo-PLGA microparticles in the targeted bifurcation channel divided by the total amount of FeCo-PLGA microparticles injected, reached 86%. The data presented in this paper confirms the feasibility of the steering of these TMMC.