Developing chiral plasmonic nanostructures represents a significant scientific challenge due to their multidisciplinary potential. Observations have revealed that the dichroic behavior of metal plasmons changes when chiral molecules are present in the system. In our study, we explored the synthesis of plasmonic gold nanoparticles and the role of cysteine on their chiroplasmonic properties.

I this context we synthesized Chiral gold nano-arrows using seed-mediated-growth synthesis method, in which gold nanorods are used as seeds while incorporating L-cysteine into growth solution as a chiral ligand. We gave evidenced that the chiral molecule transfers chirality to gold nanocrystals and the morphology is controlled through kinetic growth. The chiroplasmonic properties, such as the sign of circular dichroism, can be modulated using only one enantiomeric form in the growth solution. To understand the origin of such effect, theoretical modelling using density functional theory have been conducted. Our results point to the intermolecular cysteine interactions as a key factor in the dichroic properties of surfacemolecule chiral systems.

Experimental data consist in Electronic microscopy images (HRTEM and SEM-FEG) and chiroptical CD spectra. of gold nanoarrows obtained by seed-mediated growth in absence and presence of cysteine at different concentrations (0.9, 2.7 and 9.1microM). Each sample have been caracterized by electronic microscopy, UV-visible and Raman spectroscopy and circular dichroism.

Data are associated to a publication in open access (Nanoscale, 2024)