The Core Matters: Aggregation of Neutral Ligand-Coated Nanoparticles in Membranes

The aggregation of gold nanoparticles (AuNPs) influences their optical properties, including localized surface plasmon resonance, through plasmonic coupling between adjacent particles. For hydrophobic AuNPs embedded in lipid membranes, however, the mechanisms governing aggregation remain poorly understood. Although coarse-grained molecular dynamics simulations are well suited to study these processes, commonly used ligand-nanoparticle (NP) models neglect explicit core interactions. Here, we test whether core properties regulate NP aggregation by simulating multiple Martini NP models in a membrane environment. In contrast to the assumption that surface ligands effectively shield the core, we find that interactions with the environment remain sensitive to core parameters even at maximum ligand coverage. Furthermore, core-solvent interactions are consistent with a mechanism that directly drives nanoparticle aggregation. These results suggest that core interactions can contribute to the aggregation of functionalized nanoparticles.