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

Abstract

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.