Chiroptical Control of Gold Nanoparticle Growth through Combination of a Multimodal Chirality Inducer and Surfactant Counterion

Chiral plasmonic nanomaterials display strong interactions with circularly polarized light, offering significant potential in chirality sensing, enantioselective catalysis, and biomedical applications. While recent advances in seeded-growth synthesis have yielded complex chiral gold nanostructures through chemically induced or micelle-directed growth mechanisms, detailed intercorrelated mechanisms remain elusive. In this context, we have systematically investigated the versatility of the chiral inducer 2-amino-N-decyl-3-mercaptopropanamide (LipoCYS), which incorporates both an amino acid moiety and an aliphatic chain designed to bridge both established mechanisms. By employing cubic and octahedral achiral gold seeds and varying the surfactant halides, along with the concentration of LipoCYS, we generated a wide range of chiral morphologies, from twisted helicoids to intricate wrinkled spheres and intermediate structures. Advanced electron microscopy, including electron tomography, enabled comprehensive three-dimensional characterization and revealed distinct chiral morphological transitions and their correlations with chiroptical properties. Excellent agreement was found with the simulation results, thereby validating the representativeness of the microscopic analysis. Our findings expand the synthetic toolbox available for the precise control of nanoparticle chirality, providing deeper insights into the mechanisms of chiral growth and enhancing their potential for tailored applications.