Fig. (1).

(A) Fluorescently labeled “always-on” S6 aptamer (for A549 targeting) for fluorescence imaging in A549 xenografts. Adapted with penni ssion from reference [30]. (B) The use of S6 aptamer-Au@Ag/Au nanoparticle based AAP for fluorescence imaging in A549 xenografts. Better tumor-to-background ratio was witnessed compared with directly labeled S6 aptamer. Adapted with petmission from reference [48].