Synthetic carbon-based lanthanide upconversion nanoparticles for enhanced photothermal therapy

Photothermal therapy (PTT), a vanguard strategy in cancer/ocular neovascularization treatment, has attracted considerable attention owing to its precision, controllability, high efficacy, and minimal side effects. Nevertheless, its inherent limitations necessitate innovative solutions. One promising strategy is to develop reagents with enhanced photothermal conversion efficiency under long-wavelength laser irradiation. Carbon nanomaterials, known for their broad absorption spectra, are currently hindered by single-wavelength lasers in clinical treatments. In this study, we address this limitation by coating mesoporous carbon nanomaterials (MCNs) with a lanthanide oxysulfide up-conversion material (Y₂O₂S:Yb³⁺,Er³⁺), converting 980 nm light into visible light. This advancement enhances the photothermal conversion efficiency of the produced MCNs/Ln/GD/FR nanocomposites from 59.48% to 82.86%. Furthermore, the incorporation of gambogic acid and doxorubicin intensifies the synergistic photothermal therapy effect. A dual stimuli-responsive hydrogel (PNIPAM) is employed to ensure controlled drug release and safe delivery to tumors. Evaluations demonstrate that the MCNs/Ln/GD/FR nanocomposites exhibit exceptional tumor targeting and evident photothermal synergistic therapy effects on both subcutaneous and ocular in situ melanoma tumors by activating tumor-suppressive signaling pathways while inhibiting proliferation and differentiation-related pathways. These findings might pave the way for the development of photothermal reagent and offer valuable insights for advancing therapeutic strategies.