Choreographing Oscillatory Hydrodynamics with DNA-Coated Gold Nanoparticles

Periodic responses to non-periodic energy inputs are hallmarks of living systems, that lead to metastable features across length scales, exemplified by phenomena such as oscillations. Experimental attempts to mimic such phenomenon have primarily utilized (macro)molecular building blocks that enable precise control over interactions and thus hierarchical design. Nanoparticle-based systems have largely remained unexplored in the generation of oscillatory features. In this study, we propose a nanosystem featuring hierarchical response to light energy input where the subtle interplay of thermoplasmonic effects and reversible surface chemistry of DNA-based ligands render oscillatory hydrodynamic flows. The slow aggregation of gold nanoparticles (AuNPs) serves as a positive feedback loop, while fast photothermal disassembly acts as the negative feedback. These asymmetric feedback loops, combined with thermal hysteresis as time delay mechanism, are essential ingredients for orchestrating an oscillating response. Our findings contribute to the advancement of oscillating systems, thereby paving the way for the development of next-generation dynamic materials.