Chiral-Induced Surface-Enhanced Raman Optical Activity on a Single-Particle Substrate

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Nanotechnology

Background:

• Surface-enhanced Raman optical activity (SEROA) is valuable for analyzing molecular chirality and structural changes.
• Conventional SEROA faces challenges with substrate stability, signal uniformity, and electronic circular dichroism (ECD) interference.
• Chiral molecules often exhibit low signal efficiency in SEROA measurements.

Purpose of the Study:

• To develop a uniform and stable substrate for enhanced SEROA measurements.
• To minimize ECD interference in SEROA.
• To overcome the low signal efficiency of chiral molecules in SEROA by inducing chirality transfer.

Main Methods:

• Utilized gold nanoparticles (AuNPs) on a gold nanofilm (AuNF) structure to create stable hotspots.
• Confined hotspots to film-particle junctions to enhance SEROA signals.
• Implemented a chirality induction method using chiral molecules to influence achiral molecules.

Main Results:

• Achieved a uniform and stable substrate for SEROA measurements.
• Demonstrated successful chirality transfer, evidenced by distinguishable SEROA signals from l/d-alanine mixtures.
• Attained enantiomeric discrimination of different l/d-alanine ratios with linear responses in circular intensity difference (CID).

Conclusions:

• The proposed chiral-induced SEROA on the AuNP_on_AuNF substrate offers a promising approach for analyzing molecular chirality.
• This method enhances signal efficiency and reduces interference, overcoming limitations of conventional SEROA.
• The technique shows potential for detecting and characterizing structural changes in biomolecules, serving as a valuable research tool.