Magnetically guided Bi ₂ S ₃ @C/Fe ₃ O ₄ nanoparticles for enhanced photothermal-radiation synergy in glioblastoma treatment

Photothermal therapy (PTT) is limited by its shallow penetration depth, whereas high-dose radiotherapy (RT) can cause significant side-effects. To address these limitations, synergistic therapies integrating RT with PTT have been proposed and investigated as promising treatment strategies. In this study, multifunctional, magnetic-targeting nanoparticles that exhibit high near-infrared absorption and strong photon attenuation were successfully synthesized for the synergistic PTT-RT treatment of glioma. The platform consists of a Bi₂S₃ core encapsulated within a carbon shell. The nanoparticles were further doped with Fe₃O₄ to ensure arrival at the tumor site at an effective concentration to achieve optimal therapeutic outcomes, and to enable preferential aggregation at the intracranial tumor site under the guidance of an external magnetic field. The Bi₂S₃@C/Fe₃O₄ nanoparticles showed high biosafety and a significant synergistic therapeutic effect in combined RT and PTT, both <i>in vitro</i> and <i>in vivo</i>. The feasibility of Bi₂S₃@C/Fe₃O₄ nanoparticles for glioma treatment was systematically evaluated, providing evidence of the applicability of Bi-based nanomaterials in photothermal radiotherapy.