Quantum Dots-Based Multifunctional Nano-Prodrug Fabricated by Ingenious Self-Assembly Strategies for Tumor Theranostic

The rapid developments of quantum dots (QDs)-based nanoagents for imaging tumor and tracking drug delivery have been proven to be reliable nanodiagnostic techniques. Although abundant types of QD nanoagents have been developed for fighting against cancer, it still is a challenge to control their quality and achieve prefect repetition due to the complicated synthetic steps. The precise intermolecular self-assembly (SA) may afford a facile and low-cost strategy for this challenge. Herein, a pH and H₂O₂ dual-sensitive Sb-cyclodextrin (CD)-doxorubicin (DOX) molecule was designed to construct a QD-based theranostic prodrug (named as Sb-CD-DOX-ZAISe/ZnS) via host-guest strategy (1st SA strategy), in which QDs water-transfer and drug-uploading were integrated well. That is, the nano-prodrug (NPD) inherited highly luminescent properties from "host" QDs for bioimaging, as well as environment sensitivities from "guest" Sb-CD-DOX for drug release. Experimental results indicate that the Sb-CD-DOX-ZAISe/ZnS exhibited effectively passive tumor-targeting and could provide clear imaging for malignant tumors in metaphase or advanced stages; meanwhile, after coating with folic acid (FA) through electric attraction (2nd SA strategy), the final Sb-CD-DOX-ZAISe/ZnS@FA NPD showed expected pH-controlled negative-to-positive charge reversal ability and a better curative effect compared with free DOX. Hence, fabricating nanocomposites by highly efficient self-assembly strategies is favorable toward inorganic nanoparticles-based prodrug delivery system for tumor-targeting theranostic.