Fabricated three-dimensional (3D) upconversion nanodusters(abbreviated as EBSUCNPs) are obtained via an emulsion-based bottom-up, self assembly of NaGdF4:Yb/Er@NaGdF4 nanoparticles (abbreviated as UCNPs), Which comprise a NaGdF4:Yb/Er core and a NaGdF4 shell. The EBSUCNPs were:, then:coated with a thin: mesoporous amino-functionalized SiO2 shell (resulting in ElSgICNPs@SiO2 precursor) and further conjugated with gold nanoparticles to give the novel EBSUCNPs@SiO2@Au material. Finally, EBSDCNPs@SiO(2)gAu was-applied as a biocompatible and efficient-drug carrier for doioruhicin (DOX), thus giving rise to a multifunctional EBSVCNPs@SiO2-PDX@Au nano, composite. This final material, EBSUCNPs@SiO2 DOX@An,. and the precursor nanoparticles, EBSUCNPs@SiO2@An, were both fully characterized and their luthinescence was investigated in detail. In addition, the drug release properties and photothermal effects-of EBSUCNPs@SiO2-DOX@Au were also discussed. Interestingly, when under NIR irradiation., an increasing DOX release was achieved owing to the thermal effect of the Au NPs after ahsorhing the green light from the upconvefsion nanoclusters based on the fluorescence resonance energy transfer (FRET) effect. Thus, a near-infrared (NIR)-controlled "on-off" pattern of drug release behavior can he:achieved. Moreover, compared with a single therapy method, the assembled nanocomposites exhibit a good synergistic therapy against cancer cells that combines chemotherapy with photothermal therapy. In addition, the in vitro fluorescence microscopy images of EBSUCNPs@SiO2 DOX@Au show a higher enhancement in the red region due to the loading of DOX molecules with respect to EBSUCNPs@SiO2@Au. Therefore, this novel multifunctional 31) cluster architecture can, be used in the bioinedical field after modification and may pave a new way in Other application areas,of UCNPs cluSters.