Upconverted/downshifted NaLnF4 and metal-organic framework heterostructures boosting NIR-II imaging-guided photodynamic immunotherapy toward tumors

Heterostructures of NaLnF 4 and porphyrinic metal-organic frameworks (MOF) have been reported as a promising platform for near-infrared (NIR)-driven photodynamic therapy (PDT), while the energy transfer from NaLnF 4 to MOF greatly decreased the upconversion emissions. To develop NaLnF 4 and MOF heterostructures with significantly improved PDT and imaging simultaneously is important to track their location to implement therapy accurately. Herein, we constructed Er 3+ -doped NaLnF 4 @MOF [email protected] nanoparticles to integrate NIR-driven PDT and NIR-II imaging. NaLnF 4 nanoparticles are designed with upconversion and NIR emission simultaneously under a single 980 nm excitation, where the upconversion luminescence (UCL) overlaps well with the absorption of Zr-based porphyrin MOF, enabling efficient energy transfer from NaLnF 4 to the MOF shell to generate 1 O 2 . And the NIR luminescence, which gave out under a lower excitation power than that of UCL, could be used to track the location and distribution of the heterostructures via NIR-II imaging. Moreover, antiprogrammed death-ligand 1 (α-PD-L1) immunotherapy was introduced synergistically to improve antitumor immunity efficacy. The combination of NaLnF 4 @MOF and α-PD-L1 not only inhibited primary tumors but also suppressed distant one, leading to an effective tumor inhibition rate of 95%. This work provides an integrated nanoplatform for boosting NIR-II imaging-guided PDT/immunotherapy efficacy toward tumor treatment.