Cationic Polyelectrolyte Mediated Synthesis of MnO2-Based Core-Shell Structures as Activatable MRI Theranostic Platform for Tumor Cell Ablation

摘要

Improving nanomaterial imaging contrast is critical for disease diagnosis and treatment monitoring. Designing activatable imaging agents has the extra benefit of improving signal-to-background ratios, as well as reporting local environmental cues. MnO2, sensitive to local pH and redox state, is used to modulate the tumor microenvironment and can serve as a potential activatable magnetic resonance imaging (MRI) agent. However, the intrinsic 2D form may limit their applications in nanomedicine. Here, a novel facile aqueous route to synthesize MnO2 nanoshells on various core nanomaterials, regardless of their chemical nature and morphology, is reported. Cationic polyelectrolyte is discovered to be the key to obtain a universal method of coatingMnO(2) on nanomaterials. Taking Cu2-xSe@MnO2 as an example, a remarkable three times enhanced T-1-MRI contrast in a tumor reducing environment is demonstrated. Combined with large optical absorbance of inner Cu2-xSe cores, they can be applied for efficient redox-activated MRI-guided photothermal therapy in the NIR-II window in vitro and in vivo.