Coordination-Driven Self-Assembly of Iron Oxide Nanoparticles for Tumor Microenvironment-Responsive Magnetic Resonance Imaging

Accurate diagnosis of diseases located in deep tissues is always challenging. The always-on probe often leads to false-positive signals due to nonspecific interaction of nanoprobes. Thus, stimuli-responsive nanoprobes are highly desirable, which, however, require complicated surface modification so as to achieve trigger-induced signal changes. Here pH-triggered switch able magnetic resonance imaging (MRI) nanoprobes were constructed by coordination-driven self-assembly of monodispersed iron oxide nanoparticles (MIONPs) with simple amino acid derivatives, which displayed typical T2-weighted MRI features, yet, were turned into T1-weighted MRI under slightly acidic conditions at the tumor site. The dynamic assembly and disassembly properties of MIONPs afford T2/T1 switchable contrast imaging, enabling selective turn-on signals at the tumor site with high specificity.

Automated summary

In this study, pH-triggered switchable magnetic resonance imaging (MRI) nanoprobes were constructed by coordination-driven self-assembly of monodispersed iron oxide nanoparticles (MIONPs) with simple amino acid derivatives. These nanoprobes exhibited T2-weighted MRI features but could be turned into T1-weighted MRI under slightly acidic conditions at the tumor site. The dynamic assembly and disassembly properties of MIONPs enabled T2/T1 switchable contrast imaging, providing selective turn-on signals at the tumor site with high specificity.