One-pot synthesis of Ln3+-doped porous BiF3@PAA nanospheres for temperature sensing and pH-responsive drug delivery guided by CT imaging.

The design and synthesis of responsive inorganic nanocapsules have attracted intensive research interest in cancer treatment. The combination of non-invasive diagnosis and chemotherapy into a single theranostic nanoplatform is prospective in the biomedical field. In this work, a polyacrylic acid (PAA)-functionalized porous BiF3:Yb,Er nanocarrier was constructed via a straightforward one-pot solvothermal strategy. Compared with the undoped BiF3 sub-microspheres, the lanthanide ion (Ln3+) doping endowed the BiF3 material with a smaller size and increased BET specific surface area and pore volume, which make it suitable as a drug carrier. It was found that the synthesized nanomaterial could effectively relieve the side effects of doxorubicin (DOX) and exhibited pH-dependent DOX loading and release. Its satisfactory biocompatibility and efficient tumor inhibition were emphasized by a series of in vitro/in vivo experiments. In addition, the synthesized nanomaterial exhibited favorable CT contrast efficacy due to the excellent X-ray attenuation coefficient of Bi. Moreover, characteristic upconversion luminescence and temperature sensing in a wide temperature range were realized over the synthesized BiF3:Yb,Er sample. Therefore, carboxyl-functionalized BiF3:Yb,Er can be expected to be an ideal candidate in the fabrication of temperature sensing and multifunctional theranostic nanoplatforms.