Formation of hybrid gold nanoparticle network aggregates by specific host-guest interactions in a turbulent flow...

A multi-inlet vortex mixer (MIVM) was used to investigate the formation of hybrid gold nanoparticle network aggregates under highly turbulent flow conditions. To form aggregates, gold nanoparticles were functionalized with β-cyclodextrin (CD) and mixed with adamantyl (Ad)-terminated poly(propyleneimine) dendrimers. Adamantyl-terminated poly(ethylene glycol) was added as a stabilizer to cap the supramolecular aggregates and to provide steric repulsion. Aggregates were characterized using dynamic light scattering, UV-vis spectroscopy, and transmission electron microscopy. It was demonstrated that the growth of the aggregates is driven by specific host-guest interactions between CD and Ad moieties. The size of the supramolecular gold aggregates (20-1000 nm) was controlled by varying the ratio of the Ad and CD concentrations. The turbulent flow was found to have a minor effect on the supramolecular aggregate size at relatively low Ad/CD ratios, whereas it had a substantial effect at high Ad/CD ratios, leading to larger agglomerates in solution compared to laminar flow and manual conditions.