Multifunctional polymer vesicles for ultrasensitive magnetic resonance imaging and drug delivery

Abstract

Presented in this article is the synthesis of a new class of block copolymer, poly(ethylene oxide)-block-poly(tert-butyl acrylate-stat-acrylic acid) [PEO-b-P(AA-stat-tBA)], which can self-assemble into polymer vesicles with tuneable sizes at various conditions. The biocompatible and hydrophilic PEO chains form the vesicle coronas, while the PAA-stat-PtBA chains form the membrane. Superparamagnetic iron oxide nanoparticles (SPIONs) were generated in situ within the membrane of the polymer vesicles by nanoprecipitation. ¹H NMR, GPC, DLS, TGA, VSM and TEM were employed to characterize the structure and properties of the block copolymer, polymer vesicles and Fe₃O₄-decorated magnetic polymer vesicles. The water-dispersible, biocompatible, drug deliverable and superparamagnetic polymer vesicles exhibited excellent colloidal stability at a range of pH conditions and very high T₂ relaxivity, demonstrating ultra-sensitivity for magnetic resonance imaging and promising potential applications in nanomedicine.