Scheme 1

The schematic illustration of the construction of gold nanocages and the tumor-induced gene- and DOX-releasing mechanism. Gold nanoparticles were first decorated with thiolated-DNA-2 and thiolated anti-VEGF siRNAs based on the thiol-Au bond. PAA-1 was modified with ssDNA-1, ssDNA-3, and the AS1411 aptamer. PAA-2 was modified with ssDNA-1, ssDNA-4, and the AS1411 aptamer; then, the ssDNA-2 and siRNA-conjugated (DNA-2: siRNA = 1:10 molar ratio) gold nanoparticles were conjugated with equal molar ratios of PAA-1, PAA-2, and DNA-5 to generate the rigid trestle of the gold nanocages. The gold nanocage were finally closed through the complementary base pairing of DNA-3 and DNA-4 with DNA-5