89Zr-labeled silica nanoparticles

**89Zr-labeled silica nanoparticles** are radiopharmaceutical imaging agents consisting of mesoporous silica nanoparticles (MSNs) or dense silica nanoparticles labeled with the radioisotope zirconium-89 (89Zr, t1/2 = 78.4 hours) through a chelator-free labeling method. The labeling relies on the interaction between zirconium-89 and deprotonated silanol groups (−Si–O−) present on the silica surface and within mesoporous channels. These nanoparticles are designed for **positron emission tomography (PET) imaging** to track long-term biodistribution and fate of silica-based nanomedicines in vivo. The mesoporous structure provides enhanced stability compared to dense silica, with 89Zr detachment rates more than 20-fold slower from mesoporous channels than from dense silica surfaces. Red blood cell membrane coating (Rm-camouflaged versions) has been developed to further enhance circulation time by avoiding macrophage phagocytosis through CD47 protein presentation. These nanoparticles demonstrate exceptional in vivo stability with minimal bone uptake (<1-1.5 %ID/g) over 21 days, addressing major concerns about radioisotope-nanoparticle mismatch in traditional chelator-based systems. The technology enables accurate long-term monitoring of silica nanoparticle behavior and has potential applications in PET image-guided drug delivery for oncology. Silica is recognized as safe by the FDA (ID Code: 14808-60-7), supporting clinical translation potential.

Other names

89Zr-MSN89Zr-labeled mesoporous silica nanoparticleszirconium-89 labeled silica nanoparticleszirconium89 labeled silica nanoparticleszirconium 89 labeled silica nanoparticles