Growth of Chiral Gold Nanoparticles on Polydiacetylene Fibers Enables Plasmonic Chirality Amplification

Engineering chiral plasmonic nanostructures in solution remains a significant challenge for chiroptical applications. Here, we report a strategy to integrate self-assembled chiral polydiacetylene peptide (PDA) fibers with gold nanoparticles (AuNPs) to achieve tunable exciton–plasmon interactions and amplified chiroptical responses in aqueous milieu. The pH-responsive chiral diacetylenes (DAs) self-assemble into robust helical nanofibers that upon topochemical photopolymerization furnish PDA fibers with tunable chiral signatures. Achiral AuNPs in proximity to PDA fibers exhibit pH-dependent plasmonic chirality transfer with a maximal dissymmetry at neutral pH. A seed-mediated in-situ photoreduction of Au 3+ on chiral PDA fibers generates anisotropic AuNPs to enhance plasmonic coupling. This selective templating induces hybrid plasmon modes, giving rise to a 4-fold enhancement in dissymmetry ratios to confirm enantiomeric growth of P- and M-helical PDA–Au hybrids. These findings establish an elegant design of stereoselective chiral plasmonic nanomaterials with potential applications in biosensing, biophotonics, and metamaterials.