Figure 9.

(A) Schematic illustration of microenvironment-sensitive strategy. Triggering the accumulation of UCNPs into the tumor. (B) Mice treated with PDT agent under NIR (G 1), control agent under NIR (G 2), PDT agent without NIR (G 3), and saline under NIR (G 4). Reproduced with permission from Ai X, Ho CJH, Aw J, et al. In vivo covalent cross-linking of photon-converted rare-earth nanostructures for tumour localization and theranostics. Nat Commun. 2016;7:10432.¹⁸⁴ (C) In vivo UCL imaging of a tumor-bearing mouse after intratumoral injection of UCNPs solution into the tumor site. Reproduced with permission from Dai Y, Xiao H, Liu J, et al. In vivo multimodality imaging and cancer therapy by near-infrared light-triggered trans-platinum pro- drug-conjugated upconverison nanoparticles. J Am Chem Soc. 2013;135(50):18920–18929.¹⁸⁵ Copyright American Chemistry Society 2013.