NIR‐Light‐Activated Ratiometric Fluorescent Hybrid Micelles for High Spatiotemporally Controlled Biological Imaging and Chemotherapy

Abstract Intelligent‐responsive imaging‐therapy strategy has shown great significance for biomedicine. However, it is still a challenge to construct spatiotemporally controlled imaging‐therapy systems triggered by near infrared (NIR) light. In this work, NIR‐light‐activated ratiometric fluorescent hybrid micelles (RFHM) are prepared via the co‐assembly of upconversion nanoparticles (UCNPs), doxorubicin (DOX), and UV‐light‐responsive amphiphilic block copolymer for the spatiotemporally controlled imaging and chemotherapy. Upon NIR light irradiation, UCNPs can convert NIR light to UV light. The emitted UV light induces the photoreaction of copolymer to further trigger ratiometric fluorescence imaging and degradation of hybrid micelles, resulting in rapid DOX release from hybrid micelles for antitumor therapy. The animal experiments reveal that NIR light can not only remotely regulate the ratiometric fluorescence imaging of RFHM in tumor tissue, but also trigger DOX release from RFHM to inhibit tumor growth. Therefore, this study provides a new strategy to achieve high spatial‐temporal‐controlled biological imaging and chemotherapy.