LaB₆ nanoparticles with carbon-doped silica coating for fluorescence imaging and near-IR photothermal therapy of cancer cells

In this study, LaB₆ nanoparticles are used as a novel nanomaterial for near-infrared (NIR) photothermal therapy because they are cheaper than nanostructured gold, are easy to prepare and have an excellent NIR photothermal conversion property. Furthermore, the surface of LaB₆ nanoparticles is coated with a carbon-doped silica (C-SiO₂) shell to introduce a fluorescent property and improve stability and biocompatibility. The resulting LaB₆@C-SiO₂ nanoparticles retain the excellent NIR photothermal conversion property and exhibit a bright blue emission under UV irradiation or a green emission under visible irradiation. Using a HeLa cancer cell line, it is demonstrated that LaB₆@C-SiO₂ nanoparticles have no significant cytotoxicity, but their presence leads to remarkable cell death after NIR irradiation. In addition, from the observation of cellular uptake, the fluorescence labeling function of LaB ₆@SiO₂ (LaB₆ core/SiO₂ shell) nanoparticles is also confirmed. These results suggest that LaB ₆@C-SiO₂ nanoparticles may potentially serve as an efficient multifunctional nano-platform for simultaneous fluorescent imaging and NIR-triggered photothermal therapy of cancer cells.