Simultaneous paramagnetic and persistence-luminescence in GAGG:Ce,Pr nanoparticles synthesized by sol-gel for biomedical applications

Nanohybrid systems combining both persistent luminescence and magnetic property are recent breakthroughs in novel multimodal imaging and cancer therapy; however, integrating strategies at a common platform is complex. Herein, we report the synthesis of a Gd₃Al_5−xGa_xO₁₂:Ce³⁺,Pr³⁺ (GAGG:Ce,Pr) nanophosphor (x = 1–5) with simultaneous paramagnetic/persistence luminescence via a simple tartaric acid assisted solgel synthesis. Structural analysis revealed the formation of a pure cubic garnet crystal of GAGG:Ce,Pr, which expanded linearly upon gallium incorporation. Moreover, the novel paramagnetic/persistence luminescent material showed the formation of nanoparticles with excellent colloidal stability. Photoluminescence emission analysis showed a broad emission band in the range of λ = 500–750 nm attributed to (5d → 4f) transitions of Ce³⁺ and a sharp peak centered at λ = 612 nm attributed to electronic transitions (¹D₂→ ³H₄) within Pr³⁺ upon blue light excitation. In particular, GAGG:Ce-Pr sample with Al:Ga ratio 1:4 yielded persistent luminescence upon blue, UV, and white light excitation at room temperature. Additionally, GAGG:Ce-Pr (x = 4) nanophosphor was paramagnetic and also showed signs of weak ferromagnetism at ambient temperature. Cellular toxicity analysis in different cell lines revealed the relatively safe nature of nanoparticles at the tested concentrations. Overall, in our preliminary analysis, GAGG:Ce-Pr (x = 4) showed the persistent optomagnetic property and low cellular toxicity for potential utilization in multimodal theranostic applications.