Fig. 6

General design of fluorescent RGD-CuS-Cy5.5 nanoparticles. (a) Schematic illustration of the design and synthesis for RGD-CuS-Cy5.5 nanoparticles consisting of strong NIR absorbing CuS nanoparticles, sensitive NIR fluorophore Cy5.5 and a tumor targeting ligand cRGD. (b) Illustration of the utility of RGD-CuS-Cy5.5 for imaging-guided photothermal therapy of lymph node metastasis of gastric tumor in vivo. After i.t. injection of RGD-CuS-Cy5.5, they easily drain to lymph node due to the small nanoparticle size. The following recognition by the integrin αvβ3 overexpressed in gastric tumor cells can trigger efficient cell uptake via receptor-mediated endocytosis and subsequently accumulate in the lymph node, resulting in strong NIR fluorescence and CT contrast indicative of lymph node metastasis. Irradiation of the lymph node with an 808 nm laser to perform PTT process can cause significantly elevated temperature, which in turn triggers irreversible tumor cell death. Reproduced with permission from ref [153]