Two-thiols-regulated fabrication of plasmonic nanoparticles with co-enhanced Raman scattering and circular dichroism responses

Plasmonic nanoparticles (PNPs) with stable nanogaps are important to achieve strong, uniform and quantitative gap-enhanced Raman scattering (GERS) signals. Chiral PNPs with plasmonic circular dichroism (PCD) responses have been discovered to be suitable for applications in enantiomeric recognition, cancer therapy and activation of immune system. Herein, two-thiols-modulated growth was demonstrated to result in the acquisition of PNPs with synergistically enhanced GERS and PCD signals. 4-Aminothiophenol (4-ATP) and cysteine (Cys) played the role of Raman reporter and chiral stimulus, respectively. At a fixed 4-ATP concentration, the GERS signal of PNPs was significantly enhanced with the increase of the concentration of Cys. Simultaneously, at a fixed concentration of Cys, an increase in PCD response was observed by elevating the concentration of 4-ATP. Both aforementioned molecules acted as morphology controllers, leading to the formation of helical shell. It is suggested that the giant GERS and PCD response were contributed by the ''hot spots'' within the PNPs and more perfect helical shells. Our research pointed out a novel synthetic guideline to obtain PNPs with multiple functionalities by incorporating multi-ligands into the growth stages.

Automated summary

This study demonstrates the synthesis of plasmonic nanoparticles (PNPs) with enhanced gap-enhanced Raman scattering (GERS) and plasmonic circular dichroism (PCD) signals. By modulating the growth process with thiol molecules, the researchers were able to achieve synergistic enhancement of GERS and PCD signals. The combination of 4-aminophenol and cysteine played roles as Raman reporter and chiral stimulus, respectively. The concentration of these molecules controlled the GERS and PCD signals, and also influenced the morphology of the PNPs.