Dynamics in Anisotropic Disassembly Process of DNA-Assembled Core–Satellite Superstructure of Gold Nanoparticles at Nanometer Order

Dynamic structural transitions in DNA-assembled nanoparticle superstructures serve as analogues to molecular reactions and offer a versatile platform for various applications such as sensing and diagnostics. However, detailed insights into these dynamics have been hindered by the lack of techniques capable of directly capturing transient structures. To address this limitation, we introduce a methodology that integrates UV-vis spectroscopy with <i>in situ</i> environmental scanning electron microscopy, enabling the real-time observation of disassembly dynamics in DNA-assembled core-satellite gold nanoparticle (AuNP) superstructures. Our observations clarify that the dissociation of satellite AuNPs, triggered by target nucleic acids via strand displacement, proceeds anisotropically and is governed by steric hindrance. This steric effect induces autocatalytic reaction kinetics, as evidenced by the accelerating reaction rate over time monitored via concurrent UV-vis spectroscopic measurements. Here, we present the first direct visualization of structural dynamics in DNA-assembled AuNP systems, which may provide new perspectives on the autocatalytic reaction kinetics of programmable nanoparticle architectures.