DNA-Directed Seeded Synthesis of Gold Nanoparticles without Changing DNA Sequence

Abstract

DNA has been used for directing the growth of noble metal nanoparticles into different morphologies. Most previous studies focused on the effect of DNA sequence, while the effect of DNA adsorption was not thoroughly explored. In this work, we controlled the seeded growth of AuNPs by using the same DNA sequence but under different initial adsorption conditions: room temperature and heating. DNA adsorbed by heating induced more anisotropic nanoparticle growth, and the most effect was observed with 100 nM C30 DNA, where nanoflowers were obtained for the heated sample. By measuring DNA adsorption and desorption, heating did not increase DNA adsorption density but increased the adsorption affinity. The percentage of adsorbed DNA before the growth was only about 10%, regardless of heating, while after the growth, the associated DNA reached 75% or more, indicating that the free DNA also influenced the growth. This study offers fundamental insights into the effect of DNA adsorption on seeded AuNP growth, providing a method to tune the morphology of nanoparticles without changing DNA sequence.