Manganese-Zeolitic Imidazolate Frameworks-90 with High Blood Circulation Stability for MRI-Guided Tumor Therapy

Zeolitic imidazolate frameworks (ZIFs) as smart drug delivery systems with microenvironment-triggered release have attracted much attention for tumor therapy. However, the exploration of ZIFs in biomedicine still encounters many issues, such as inconvenient surface modification, fast drug release during blood circulation, undesired damage to major organs, and severe in vivo toxicity. To address the above issues, we developed an Mn-ZIF-90 nanosystem functionalized with an originally designed active-targeting and pH-responsive magnetic resonance imaging (MRI) Y₁ receptor ligand [Asn²⁸, Pro³⁰, Trp³²]-NPY (25-36) for imaging-guided tumor therapy. After Y₁ receptor ligand modification, the Mn-ZIF-90 nanosystem exhibited high drug loading, better blood circulation stability, and dual breast cancer cell membrane and mitochondria targetability, further favoring specific microenvironment-triggered tumor therapy. Meanwhile, this nanosystem showed promising T₁-weighted magnetic resonance imaging contrast in vivo in the tumor sites. Especially, this nanosystem with fast clean-up had almost no obvious toxicity and no damage occurred to the major organs in mice. Therefore, this nanosystem shows potential for use in imaging-guided tumor therapy.