Design And Principle Of Core-shell Structures For Enhanced Photothermal Conversion And Its Application In Tumor Diagnosis And Treatment

Upconversion nanoparticles?UCNPs?have great potential to apply in integrated probes for diagnosis and treatment for its advantages of large Stokes shift,weak light bleaching,low toxicity,good stability and adjustable emission spectrum from ultraviolet?UV?to visible?Vis?light and near infrared?NIR?.However,given the limited function of individual UCNPs,much effort has been devoted to combine it with other functional components to achieve multifunctional effects,of which the inorganic sulfide semiconductor is an excellent photosensitizer.Depending on the mechanism of energy transfer,it can be excited by UCNPs emitted light through irradiation energy transfer?IET?and fluorescence resonance energy transfer?FRET?to obtain ideal results.However,the lattice mismatch between UCNPs and sulfides makes the construction of UCNPs/sulfide-based fluorescence resonance energy systems with application exploration a very challenging task.Therefore,as a continuation of our previous work,an amorphous layer(AA-[Zn?OH?₄]^2-)is formed on the outside of UCNPs,and then Zn S was coated on the surface of UCNPs,so a FRET system combining UCNPs and Zn S was obtained.The application of UCNPs@Zn S has been explored in the field of biomedicine.More diverse UCNPs@AgBiS₂ was desgined basic on the previous work afterward.Here we prepared a pure-phase AgBiS₂ coated UCNPs system by adjusting the molar ratio of Ag and Bi accourding to the previous synthesis route.Through a series of active oxygen probes,the FRET system was investigated to generate reactive oxygen species.Moreover,by designing specific upconversion nanoparticles,it was proved that the system improves its photothermal conversion capacity through core-shell structure by collecting a series of photothermal data.We have verified that the system mentioned above has a good inhibitory effect on tumor tissues of mice by testing the ability of killing tumor cells in vitro cell experiments,which shows that it has the potential to become an inorganic nanomedicine.