Temperature-Cycling-Guided Self-Assembly of DNA-Functionalized Nanoparticles for Avoiding Kinetic Traps.

Abstract

The self-assembly of DNA-functionalized gold nanoparticles is often hindered by kinetic traps arising from excessively strong interparticle interactions, leading to structural defects. To address this, we propose a novel temperature-cycling strategy that reversibly modulates hydrogen bonding between DNA strands (<i>T</i>_high/<i>T</i>_low). The high-temperature phase supplies energy to escape metastable and misbound states, enhancing particle mobility for local reorganization, while the low-temperature phase promotes hydrogen bond reformation and defect reorganization, driving the system toward a more stable state. By combining theoretical modeling, coarse-grained molecular dynamics simulations, and experimental validation, we demonstrate that this strategy delivers sustained, periodic energy input leveraging cooperative interparticle effects to perturb defect regions. This guides the system across free energy barriers, enabling the efficient formation of defect-free crystals. This work elucidates the assembly kinetics via this nonequilibrium pathway, highlighting the potential for broader applications in other self-assembly systems plagued by kinetic traps.