A Multiscale Modeling Approach to Chiral Nanocluster Self-assembly

The controlled formation of chiral microstructures from functionalized nanoparticles remains a key challenge in nanoscience. Factors such as ligand charge, counterion type, and pH critically affect nanoparticle self-assembly, yet molecular-level mechanisms remain poorly understood. In this study, we used atomistic and coarse-grained (CG) molecular dynamics (MD) simulations to investigate the self-assembly of [Ag$_9$(\textit{o}-MBA)$_9$]$^{9-}$ (where \textit{o}-MBA = \textit{ortho}-mercaptobenzoic acid) in the presence of calcium ions. Atomistic MD simulations revealed dynamic silver cores and site-specific Ca$^{2+}$ binding, which promotes the formation of ordered motifs. CG MD simulations enabled us to simulate large multimeric systems with hundreds of nanoclusters over extended timescales. Together, the simulations show that nanoclusters assemble into long linear chains, which subsequently coil into chiral superstructures. These findings provide multiscale, molecular-level insight into how calcium-mediated interactions guide the chiral self-assembly of monolayer-protected metal nanoclusters and establish a computational framework for the rational design of chiral nanomaterials.