Core–shell SrTiO3:Yb3+,Er3+@mSiO2 nanoparticles for controlled and monitored doxorubicin delivery

The investigation of nano-carriers with controllable and trackable drug release kinetics has attracted worldwide attention for new tumor theranostic strategies with catabatic side effects. Herein, a range of monodispersed core–shell structured photoluminescent SrTiO3:Yb3+,Er3+@mSiO2 nanoparticles were designed and synthesized. The surfactant cetyltrimethylammonium bromide (CTAB) was used to vary the microstructure of the mesoporous SiO2 shell. The specific surface area and pore volume increase proportionally with the content of CTAB. Consequently, the doxorubicin (DOX) loading capacity increases, and the drug release kinetics possesses a sustained behaviour. More importantly, the DOX release kinetics was found to correspond well to the evolution of the up-conversion luminescence (UCL) phenomenon. More rapid drug release induces more rapid photoluminescence enhancement, and vice versa. This study has therefore been anticipated to suggest another promising multifunctional drug delivery platform for advanced chemotherapies.