NIR-activated upconversion nanoparticles/hydrogen-bonded organic framework nanocomposites for NIR-II imaging-guided cancer therapy

Developing hydrogen-bonded organic frameworks (HOFs) materials and exploring their applications in cancer therapy show broad prospects. However, most HOFs are limited by the penetration depth of UV-Vis light in biological tissues required for their activation. Herein, NIR-activated upconversion nanoparticles/HOFs (abbreviated as UHOFs) nanocomposites composed of NaYF4:Yb3+/Er3+@NaYF4:Nd3+@NaYF4 (abbreviated as CSS) and PFC-55 HOFs are synthesized through a ligand-graft stepwise method to address the challenge. CSS can not only emit visible light but also NIR-II fluorescence under 808 nm laser excitation. The visible light can effectively excite PFC-55 HOFs to generate singlet oxygen and photothermal effect. Moreover, the NIR-II of Nd3+ is used for fluorescence imaging. After modifying CSS@PFC-55 (CSS@P) with polyacrylic acid (PAA), the resulting CSS@P-PAA exhibit good biocompatibility and efficient cancer ablation ability. To our knowledge, as the first demonstration, NIR-activated UHOFs for NIR-II imaging-guided photodynamic/photothermal combination cancer therapy, which open new avenues for exploring HOFs materials for non-invasive deep cancer therapy.