Phototheranostic LPP‐QDs‐IR‐820 Nanocomposites for Specific NIR‐II Imaging of Lymphatic and Photothermal Therapy of Cervical Tumors

Abstract Precise theranostics of tumors is intricately linked to the early detection and monitoring of lymph nodes (LN) and metastases, making the targeted localization of LNs essential for tumor identification. However, designing LN‐targeting probes remains a significant challenge due to issues such as lymphatic uptake, biocompatibility, and fluorescence stability. To address these challenges, near‐infrared II (NIR‐II) fluorescence probes are developed through meticulous analysis of LN physiological structure and passive targeting strategy for LN detection and tumor therapy. An LPP‐QDs‐IR‐820 nanocomposite (NCs) is engineered, comprising the IR‐820 molecules and ultrabright PbS@CdS quantum dots (QDs), which are encapsulated within a liposome‐SH‐mPEG 2000 polymer matrix. These NCs demonstrates remarkable lymphatic enrichment, facilitating real‐time tracking of LN via electrostatic repulsion and extracellular matrix effects. Importantly, the NCs exhibit negligible in vivo toxicity and high biocompatibility. The intense NIR‐II fluorescence emissions of IR‐820 and PbS@CdS QDs confer upon the NCs a high NIR‐II fluorescence quantum yield (6%). The cervical tumors and their deep microvessels are clearly observed via NIR‐II fluorescence imaging. Moreover, the photothermal properties of IR‐820 enable the NCs to achieve a photothermal conversion efficiency of 36.56%, leading to effective photothermal therapy in cervical tumor mice.