Supramolecular Tropism Driven Aggregation of Nanoparticles In Situ for Tumor‐Specific Bioimaging and Photothermal Therapy

Inorganic nanomedicine has attracted increasing attentions in biomedical sciences due to their excellent biocompatibility and tunable, versatile functionality. However, the relatively poor accumulation and retention of these nanomedicines in targeted tissues have often hindered their clinical translation. Herein, highly efficient, targeted delivery, and in situ aggregation of ferrocene (Fc)‐capped Au nanoparticles (NPs) are reported to cucurbit[7]uril (CB[7])‐capped Fe3O4 NPs (as an artificial target) that are magnetically deposited into the tumor, driven by strong, multipoint CB[7]‐Fc host–guest interactions (here defined as “supramolecular tropism” for the first time), leading to high tumor accumulation and retention of these NPs. The in vitro and in vivo studies demonstrate the precisely controlled, specific accumulation, and retention of Au NPs in the tumor cells and tissue via supramolecular tropism and in situ aggregation, which afford locally enhanced CT imaging of cancer and enable tumor‐specific photothermal therapy attributed to the plasmonic coupling effects between adjacent Au NPs within the supramolecular aggregations. This work provides a novel concept of supramolecular tropism, which may drive targeted delivery and enable specific accumulation, retention, and activation of nanomedicine for improved bioimaging and therapy of cancer. Upon magnetically depositing cucurbit[7]uril‐capped Fe3O4 nanoparticles into the tumor tissue, ferrocene‐capped Au nanoparticles are specifically delivered to the tumor site and form supramolecular aggregates in situ, driven by supramolecular tropism mediated via strong, multipoint host‐guest interactions. Precisely controlled, high tumor accumulation and retention of these nanoparticles in tumor site significantly enhanced CT imaging and led to locally‐activated photothermal therapy.