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Visualization of Multimerization and Self-Assembly of DNA-Functionalized Gold Nanoparticles Using In-Liquid Transmission Electron Microscopy

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posted on 2015-11-19, 00:00 authored by Sercan Keskin, Stephanie Besztejan, Günther Kassier, Stephanie Manz, Robert Bücker, Svenja Riekeberg, Hoc Khiem Trieu, Andrea Rentmeister, R. J. Dwayne Miller
Base-pairing stability in DNA-gold nanoparticle (DNA-AuNP) multimers along with their dynamics under different electron beam intensities was investigated with in-liquid transmission electron microscopy (in-liquid TEM). Multimer formation was triggered by hybridization of DNA oligonucleotides to another DNA strand (Hyb-DNA) related to the concept of DNA origami. We analyzed the degree of multimer formation for a number of samples and a series of control samples to determine the specificity of the multimerization during the TEM imaging. DNA-AuNPs with Hyb-DNA showed an interactive motion and assembly into 1D structures once the electron beam intensity exceeds a threshold value. This behavior was in contrast with control studies with noncomplementary DNA linkers where statistically significantly reduced multimerization was observed and for suspensions of citrate-stabilized AuNPs without DNA, where we did not observe any significant motion or aggregation. These findings indicate that DNA base-pairing interactions are the driving force for multimerization and suggest a high stability of the DNA base pairing even under electron exposure.