Cell Internalizable and Intracellularly Degradable Cationic Polyurethane Micelles as a Potential Platform for Efficient Imaging and Drug Delivery

Abstract

A cell internalizable and intracellularly degradable micellar system, assembled from multiblock polyurethanes bearing cell-penetrating gemini quaternary ammonium pendent groups in the side chain and redox-responsive disulfide linkages throughout the backbone, was developed for potential magnetic resonance imaging (MRI) and drug delivery. The nanocarrier is featured as a typical “cleavable core–internalizable shell–protective corona” architecture, which exhibits small size, positive surface charge, high loading capacity, and reduction-triggered destabilization. Furthermore, it can rapidly enter tumor cells and release its cargo in response to an intracellular level of glutathione, resulting in enhanced drug efficacy <i>in vitro</i>. The magnetic micelles loaded with superparamagnetic iron oxide (SPIO) nanoparticles demonstrate excellent MRI contrast enhancement, with <i>T</i>₂ relaxivity found to be affected by the morphology of SPIO-clustering inside the micelle core. The multifunctional carrier with good cytocompatibility and nontoxic degradation products can serve as a promising theranostic candidate for efficient intracellular delivery of anticancer drugs and real-time monitoring of therapeutic effect