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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 Cu 3 BiS 3 nanoparticles (NPs) is fabricated for tumour-targeted combination phototherapy. The as-synthesized hydrophobic Cu 3 BiS 3 NPs are modified with DSPE-PEG/DSPE-PEG-NH 2 , 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 Gd 3+ . The rationally designed Cu 3 BiS 3 -PEG-(Ce6-Gd 3+ )-FA NPs, which have high physiological stability and good biocompatibility, can specifically target FA-receptor over-expressed tumour cells. The Cu 3 BiS 3 -PEG-(Ce6-Gd 3+ )-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.

Conventional wide bandgap semiconductors can absorb UV/visible light but have no photoabsorption band in the near-infrared (NIR) region, leading to difficulty in their use as NIR-responsive agents. With TiO 2 as an example, we report the tuning from UV-responsive TiO 2 nanocrystals to blue TiO 2 nanocrystals with newly appeared NIR absorption band through the Nb-doping strategy. A strong NIR band should result from the localized surface plasmon resonances due to the considerable free electrons originating from the efficient incorporation of Nb 5+ ions (<15.5%). Interestingly, under the irradiation of a 1064 nm laser, Nb-doped TiO 2 nanocrystals can convert laser energy into heat, and higher Nb-doping content can lead to higher NIR-induced temperature elevation, highlighting that the photothermal performances of TiO 2 nanocrystals can be dynamically modulated by adjusting the Nb-doping levels. After coating with PEGylated phospholipid, the resulting nanocrystals display water dispersibility, high photothermal conversion efficiency and cytocompatibility. Therefore, these Nb-doped TiO 2 nanocrystals can be used as efficient and heavy-metal-free nanoagents for the simultaneous NIR/photoacoustic imaging and photothermal therapy of tumors using a 1064 nm laser in the second biological window.