Fig. 6. (a) Schematic illustration of Dox drug release from hpDNA-modified NaYF4@SiO2–Au nanoconjugates, triggered by a photon upconversion process. (b) TEM images of the NaYF4@SiO2–Au nanoparticles. (c) CCD imaging of NIR (800 nm), red (660 nm), and green (540 nm) emissions, recorded for the as-prepared NaYF4@SiO2–Au nanoconjugates and NaYF4:Yb/Er (18 : 2 mol%) @NaYF4 nanocrystals, under pork muscle tissues of different depth. False-color images were taken under the 980 nm laser excitation. (d) In vivo upconversion imaging of the tumor-bearing mouse treated with the DNA-modified nanoconjugates. (e) Volumetric changes of the HeLa tumor, compiled as a function of duration time in four different modes of treatment. The tumor volume was normalized to their initial sizes. (f) The corresponding photographs of the tumor-bearing mice taken after various treatments. Reproduced with permission from ref. 42, copyright: 2017, Wiley.
