Highly doped NaErF_(4)-based nanocrystals for multi-tasking application

How to engineer single nanocrystal to achieve multiple functions is still a huge challenge.In this work,a novel highly doped rare earth nanocrystal NaErF_(4)@NaGdF_(4)@NaDyF_(4)(Er@Gd@Dy)was designed and fabricated,which exhibits various performances by itself,including the longitudinal(T1)and transverse relaxation time(T2)double-mode magnetic resonance imaging(MRI),upconversion luminescence and down-shifting luminescence.Upon irradiation of 808 nm near-infrared(NIR)light,the upconverted red light can indirectly activate the photo sensitizer Ce6 conjugated on the surface of nanocrystals for photodynamic therapy(PDT).In vivo experiments demonstrate that the nano materials can eradicate notably primary tumors without obvious systematic toxicity.In addition,the longitudinal and transverse relaxation rates of Er@Gd@Dy are 24.83 and 319.86(mmol/L)^(-1)/s,respectively,which are superior to those of the nanocrystals reported previously.Simultaneously,the nanocrystals have the ability to generate NIR-Ⅱlight located at 1530 nm,favorable in bioimaging in deeper tissues.As a consequence,this new nanoplatform will advance the improvement of multimodal imaging guided tumor diagnosis and treatment.