Chiral sensing of glucose by surface-enhanced Raman spectroscopy

• Published in: Analytica chimica acta Vol. 1330; p. 343290
• Main Authors: Lee, Daedu, Pang, Yoonsoo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 22.11.2024
• Subjects: Chiral sensing; Glucose; Phenylalanine; Surface adsorption geometry; Surface-enhanced Raman spectroscopy; Chiral sensing; Glucose; Phenylalanine; Surface adsorption geometry; Surface-enhanced Raman spectroscopy
• ISSN: 0003-2670
• DOI: 10.1016/j.aca.2024.343290

Chiral-selective molecular interactions are considered crucial in numerous physiological processes. Chiral-selective analytical methods of biomolecules with sufficient sensitivity are of great interest in numerous applications. Several surface-enhanced Raman scattering (SERS)-based methods have recently been reported for chiral sensing of biomolecules. However, the lack of molecular-level understanding of SERS spectral changes of reporter and analyte molecules may mislead the development of chiral detection methods. We report the chiral sensing of glucose (Glu) by SERS of L- and D-phenylalanine (Phe) with colloidal gold nanoparticles (AuNPs) synthesized by borohydride ions. The Phe SERS showed drastic spectral changes only when Glu of the same chirality as Phe was added, which also showed strong dependence on Glu concentration. The increase of δ(COO−) and decrease of νs(COO−) modes in Phe SERS, exclusively observed with the chiral-selective bimolecular interactions of chirally matching Glu, are understood as modified surface adsorption geometry of the carboxylate group. Quantitative spectral analysis for the Glu concentration of a specific chirality showed the detection limit down to 2 × 10−9 - 2 × 10−7 M levels depending on the existence of the opposite enantiomer of Glu. In this study, we demonstrated that the Phe SERS on AuNPs can be utilized in the chiral sensing of Glu molecules with quantitative concentration analysis. The bimolecular interactions of surface-adsorbed Phe and chirally matching Glu are suggested for the chiral recognition of Phe SERS. These results imply that a molecule-level understanding is indispensable for developing SERS-based chiral sensing methods. [Display omitted] •Phenylalanine adsorbed on gold nanosurfaces becomes the chiral probe of glucose.•Glucose of the same chirality as phenylalanine changes the phenylalanine SERS.•Glucose concentrations down to 10−9 or 10−7 M are quantitatively determined.•Chiral-sensitive SERS is applicable to numerous biological chiral samples.