In Vivo Tracking of the Degradation of Mesoporous Silica through ⁸⁹ Zr Radio‐Labeled Core–Shell Nanoparticles

While mesoporous silica nanoparticles (MSNs) are extensively studied as high-potential drug delivery platforms, the successful clinical translation of these nanocarriers strongly depends on their biodistribution, biodegradation, and elimination patterns in vivo. Here, a novel method is reported to follow vivo degradation MSNs by tracking radioactive label embedded structure. Core–shell (NPs) with dense core shell labeled low quantities positron emitter 89Zr, either or shell. In emission tomography imaging ex organ measurements reveal remarkable difference 89Zr biodistribution between shell-labeled core-labeled NPs. Release radiotracer from NPs used probe extent dissolution, prompt release radioisotope observed, partial excretion already first 2 h post injection, slower accumulation bones over time. On other hand, when nanoparticle core, remains largely unchanged during 6 h. These findings indicate that have fast, hour-scale, kinetics