On the synthesis of chiral gold nanorods

Chirality at the nanoscale has emerged as a powerful design parameter for engineering light-matter interactions, catalytic activity, and biological recognition. Among inorganic nanomaterials, plasmonic gold nanostructures are particularly attractive owing to their tunable optical resonances and compatibility with biological environments. However, reproducible synthesis of chiral gold nanoparticles and systematic evaluation of their interactions with neural tissue remain limited. Here, we present a robust method to synthesize left- and right-handed chiral gold nanorods with controlled morphology and high enantiomeric purity. We identify precursor and chiral inducer concentration regimes that direct the enantioselective formation of chiral rods or branched structures. Further, we quantify their synergistic effect on the catalytic activity of redox enzymes using lactate dehydrogenase as a representative example. Lastly, we interface these chiral nanorods with neuroblastoma and astrocyte cell lines to evaluate cell viability and with an osteosarcoma cell line to assess cell morphology responses as a function of particle shape and chirality. Our findings reveal no enantioselective effects on short-term cell viability or morphology, suggesting that, in our hands, nanoscale chirality does not affect cell behavior beyond conventional concentration-dependent effects. Altogether, this work provides a comprehensive framework linking synthesis and properties of chiral gold nanorods and positioning them as non-toxic candidates towards future efforts in neuro-nanomedicine.