Monovalent DNA–gold nanoparticle (mDNA–AuNP) conjugates hold great promise for widespread applications, especially the construction of well-defined, molecule-like nanosystems. Previously reported methods all rely on the use of thiolated DNA to functionalize AuNPs, resulting in relatively low yields. Here, we report a facile method to rapidly prepare mDNA–AuNPs using a poly-adenine (polyA)-mediated approach. As polyA can selectively bind to AuNPs with high controllability of the surface density of DNA, we can use a DNA strand with a sufficiently long polyA to wrap around the surface of an individual AuNP, preventing further the adsorption of additional strands. Based on this observation, we obtained mDNA–AuNPs with a nearly quantitative yield of ~90% using 80 As, as confirmed by both gel electrophoresis and transmission electron microscope observation. The yields of mDNA–AuNPs were insensitive to the stoichiometric ratio between DNA and AuNPs, suggesting the click chemistry-like nature of this polyA-mediated reaction. mDNA–AuNPs exhibited rapid kinetics and high efficiency for sequence-specific hybridization. More importantly, we demonstrated that AuNPs of fixed valences could form well-defined heterogenous oligomeric nanostructures with precise, atom-like control.
NPG Asia Materials (2015) 7, e159.
Clicking DNA to gold nanoparticles: poly-adenine-mediated formation of monovalent DNA-gold nanoparticle conjugates with nearly quantitative yield
Guangbao Yao, Hao Pei, Jiang Li, Yun Zhao, Dan Zhu, Yinan Zhang, Yunfeng Lin, Qing Huang, Chunhai Fan