Sensitive Activatable Nanoprobes for Real‐Time Ratiometric Magnetic Resonance Imaging of Reactive Oxygen Species and Ameliorating Inflammation In Vivo

Imaging-guided real-time monitoring of the treatment process of inflammatory diseases is important for the timely adjustment of treatment planning to lower unnecessary side effects and improve treatment outcomes. However, it is difficult to reflect the dynamic changes of inflammation in vivo with enough tissue penetration depth. Here a novel nanotheranostic agent (denominated TMSN@PM) with platelet membrane (PM)-coated, tempol-grafted, manganese-doped, mesoporous silica nanoparticles is developed. The PM endows the TMSN@PM with the ability to target inflammation sites, which are verified by fluorescence imaging with Cyanine5 carboxylic acid (Cy5)-labeled TMSN@PM. Under the inflammatory environment (mild acidity and excess reactive oxygen species (ROS)), TMSN@PM can scavenge the excess ROS, thereby alleviating inflammation, degrade, and release manganese ions for enhanced magnetic resonance imaging (MRI). The relaxation changes (ΔR₁ ) are almost linearly correlated with the concentration of H₂ O₂ , which can reflect the degree of inflammation. This method offers a non-invasive imaging-based strategy for early prediction of the therapeutic outcomes in inflammatory therapy, which may contribute to precision medicine in terms of prognostic stratification and therapeutic planning in future.