Gold-DNA nanosunflowers for efficient gene silencing with controllable transformation.

The development of an efficient delivery system for enhanced and controlled gene interference-based therapeutics is still facing great challenges. Fortunately, the flourishing field of nanotechnology provides more effective strategies for nucleic acid delivery. Here, the triplex-forming oligonucleotide sequence and its complementary strand were used to mediate self-assembly of ultrasmall gold nanoparticles. The obtained sunflower-like nanostructures exhibited strong near-infrared (NIR) absorption and photothermal conversion ability. Upon NIR irradiation, the large-sized nanostructure could disassemble and generate ultrasmall nanoparticles modified with c-myc oncogene silencing sequence, which could directly target the cell nucleus. Moreover, the controlled gene silencing effect could be realized by synergistically controlling the preincubation time with the self-assembled nanostructure (in vitro and in vivo) and NIR irradiation time point. This study provides a new approach for constructing more efficient and tailorable nanocarriers for gene interference applications.