Supramolecular domains in mixed peptide self-assembled monolayers on gold nanoparticles

Self-organization in mixed self-assembled monolayers of small molecules provides a route towards nano-particles with complex molecular structures. Inspired by a structural biology a strategy based on chemical cross linking is introduced to probe proximity between functional peptide embedded in a mixed self-assembled monolayer at the surface os a nanoparticle. The physical basis of the proximity measurement is a transition from intramolecular to intermolecular cross-linking as the functional peptides get closer. Experimental investigations for a binary peptide self-assembled monolayer show that this transition happens at an extremely low molar rate of the functional versus matrix peptide. Molecular dynamics simulations at the volume explored by the reactive groups. Comparison of the experimental results with a probabilistic model demonstrates that the peptides are not randomly distributed at the surface of the nanoparticle but rather self-organize into supramolecular domains.