Chargeable persistent luminescence 3D-printed scaffolds: A stepwise tactic for osteosarcoma treatment

Osteosarcoma is the most frequent malignant primary bone tumor with a poor prognosis and remains a significant issue in clinics due to the unrepairable bone defect following surgery and the lingering tumor cells. Photodynamic therapy (PDT) with its non-invasive nature and spatiotemporally controllable feature exhibits specific therapeutic efficiency, but it is limited by phototoxicity caused by prolonged laser exposure. Herein, we design and engineer an irradiation-free bifunctional PDT scaffold (BG@SAO-RB) by integrating persistent luminescence material (SrAl2O4:Eu, Dy) and photosensitizer (rose bengal) into a 3D-printed bioactive glass scaffold for stepwise osteosarcoma elimination and bone defect repair. Owing to the design of a rechargeable internal light source, the constructed scaffolds with reactive oxygen species generation ability attain long-term and efficient PDT for osteosarcoma, leading to tumor cell killing and proliferative inhibition. The findings from tumor growth characteristics and pathological sections also confirm that BG@SAO-RB scaffolds achieve successful osteosarcoma ablation through long-term PDT in tumor-bearing nude mice. Notably, the as-designed scaffolds promote osteogenic differentiation of rat bone marrow mesenchymal stem cells and accelerate bone regeneration, which was evidenced by the improved radiological and histological manifestations. This work broadens the biomedical application of persistent luminescence materials and implicates an efficient treatment paradigm for osteosarcoma elimination and subsequent bone tissue regeneration.