Rechargeable\nAfterglow Superclusters for NIR-Excitable\nRepetitive Phototherapy

Afterglow luminescence has attracted increasing attention\ndue to\nits prolonged emission, reduced autofluorescence, and minimized photodamage.\nHowever, persistent luminescence typically requires high-energy excitation\n(e.g., ultraviolet and visible light), which has limited tissue penetration.\nHerein, we have developed a one-pot surface segregation strategy to\nconstruct NIR-excitable afterglow superclusters (UCZG-SCs) by modularly\nassembling spinel-phase afterglow nanoparticles (Zn<sub>1.1</sub>Ga<sub>1.8</sub>Ge<sub>0.1</sub>O<sub>4</sub>:Cr<sup>3+</sup>) and hexagonal-phase\nupconversion nanoparticles (NaYF<sub>4</sub>:Yb,Tm​@NaLuF<sub>4</sub>:Y). Since the proposed methodology does not require crystal\nlattice similarity, it enables fabrication of various NIR-excitable\npersistent superclusters with great flexibility in size, composition,\nand luminescent profiles. As a proof of concept, an injectable persistent\nimplant is established by embedding UCZG-SCs in the oleosol of poly(lactic-<i>co</i>-glycolic acid)/<i>N</i>-methylpyrrolidone,\nwhich serves as an inner-body lamp to excite photosensitizers for\nphotodynamic therapy. With its excellent charging–recharging\nstability, a repetitive phototherapy under periodic 980 nm light illumination\nis accomplished, which significantly improves phototherapeutic efficiency\nand restrains tumor growth.