Functionalized Cu₃BiS₃ nanoparticles for dual-modal imaging and targeted photothermal/photodynamic therapy

Multifunctional nano-biomaterials with the integration of diagnostic and therapeutic functions have shown great promise in improving the efficacy of cancer therapy. Herein, a new nanoplatform based on functionalized Cu₃BiS₃ nanoparticles (NPs) is fabricated for tumour-targeted combination phototherapy. The as-synthesized hydrophobic Cu₃BiS₃ NPs are modified with DSPE-PEG/DSPE-PEG-NH₂, followed by the conjugation of the photosensitizer chlorin e6 (Ce6) and the target ligand folic acid (FA). The introduced Ce6 can further form a chelate complex with Gd³⁺. The rationally designed Cu₃BiS₃-PEG-(Ce6-Gd³⁺)-FA NPs, which have high physiological stability and good biocompatibility, can specifically target FA-receptor over-expressed tumour cells. The Cu₃BiS₃-PEG-(Ce6-Gd³⁺)-FA NPs exhibit effective dual-modal CT and MR imaging in the xenografted HeLa tumours. Importantly, excellent in vivo anti-tumour effects have been achieved by synergistic photothermal/photodynamic therapy using the multifunctional NPs. We expect that this versatile nanoplatform will play a role in exploring precise cancer diagnosis and therapy.