DNA-directed gold and silver bimetal nanoparticle and preparation method and application thereof

The invention provides a DNA-directed gold and silver bimetal nanoparticle and a preparation method thereof. The preparation method includes the following steps that firstly, the surface of a gold nanosphere is modified through a hairpin DNA molecule, a gold nanosphere/hairpin DNA compound is prepared, and then with the gold nanosphere/hairpin DNA compound as the seed, in a solution system, silvernitrate is reduced on the surface of the seed in situ through a reducing agent and grows into a gold and silver bimetal nanometer mushroom. The invention further provides the hairpin DNA-directed gold and silver bimetal nanoparticle obtained through the preparation method, and the morphology of the DNA-directed gold and silver bimetal nanoparticle is a nuclear shell shape with gold completely wrapped by silver or a mushroom shape with the gold partially wrapped by the silver. Compared with the prior art, the preparation method for forming the gold and silver bimetal nanometer mushroom particle by using hairpin DNA as