Analysis of Ergothioneine Using Surface-Enhanced Raman Scattering: Detection in Mushrooms

Surface-enhanced Raman scattering (SERS) spectroscopy is a straightforward analytical technique capable of providing detailed information about metabolites in biological samples. The objective of this study was to perform a SERS analysis of ergothioneine (EGT), an amino acid synthesized by microbes...

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Main Authors: Federico Puliga, Veronica Zuffi, Alessandra Zambonelli, Pavol Miškovský, Ornella Francioso, Santiago Sanchez-Cortes
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Chemosensors
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Online Access:https://www.mdpi.com/2227-9040/13/6/213
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author Federico Puliga
Veronica Zuffi
Alessandra Zambonelli
Pavol Miškovský
Ornella Francioso
Santiago Sanchez-Cortes
author_facet Federico Puliga
Veronica Zuffi
Alessandra Zambonelli
Pavol Miškovský
Ornella Francioso
Santiago Sanchez-Cortes
author_sort Federico Puliga
collection DOAJ
description Surface-enhanced Raman scattering (SERS) spectroscopy is a straightforward analytical technique capable of providing detailed information about metabolites in biological samples. The objective of this study was to perform a SERS analysis of ergothioneine (EGT), an amino acid synthesized by microbes and fungi, across a range of pH values (acidic to alkaline) and concentrations (2 × 10<sup>−5</sup> M to 2 × 10<sup>−7</sup> M), to understand the dynamic interactions between EGT and silver (Ag) nanoparticles. Furthermore, SERS was applied in situ on mushroom fruiting bodies to detect the presence of EGT. The SERS spectra revealed that the interaction of EGT with Ag nanoparticles underwent significant alterations at varying pH levels, primarily due to isomerization. These changes were associated with modifications in the aromaticity and ionization of the imidazole ring, driven by both metal adsorption and alkaline conditions. Our results indicated the formation of distinct tautomeric forms of the imidazole group, namely the thione and thiol forms, in aqueous solution and on the Ag surface, respectively. Furthermore, the EGT spectra at different concentrations suggested that ionization occurred at lower concentrations. Notably, the SERS spectra of the mushroom fruiting bodies were dominated by prominent bands attributable to EGT, as corroborated by the comparison with the EGT fungal extract and EGT standard. These findings underscore the utility of SERS spectroscopy as a rapid and effective tool for obtaining comprehensive molecular fingerprints, even directly from complex biological matrices such as mushroom fruiting bodies.
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spelling doaj-art-fb733690271f40e09d05801e3002827f2025-08-20T02:24:34ZengMDPI AGChemosensors2227-90402025-06-0113621310.3390/chemosensors13060213Analysis of Ergothioneine Using Surface-Enhanced Raman Scattering: Detection in MushroomsFederico Puliga0Veronica Zuffi1Alessandra Zambonelli2Pavol Miškovský3Ornella Francioso4Santiago Sanchez-Cortes5Department of Agricultural and Food Sciences, University of Bologna, Viale G. Fanin 40-50, 40127 Bologna, ItalyDepartment of Agricultural and Food Sciences, University of Bologna, Viale G. Fanin 40-50, 40127 Bologna, ItalyDepartment of Agricultural and Food Sciences, University of Bologna, Viale G. Fanin 40-50, 40127 Bologna, ItalySAFTRA Photonics s.r.o., Moldavská cesta 51, 040 11 Košice, SlovakiaDepartment of Agricultural and Food Sciences, University of Bologna, Viale G. Fanin 40-50, 40127 Bologna, ItalyInstituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas (IEM-CSIC), Serrano, 121, E-28006 Madrid, SpainSurface-enhanced Raman scattering (SERS) spectroscopy is a straightforward analytical technique capable of providing detailed information about metabolites in biological samples. The objective of this study was to perform a SERS analysis of ergothioneine (EGT), an amino acid synthesized by microbes and fungi, across a range of pH values (acidic to alkaline) and concentrations (2 × 10<sup>−5</sup> M to 2 × 10<sup>−7</sup> M), to understand the dynamic interactions between EGT and silver (Ag) nanoparticles. Furthermore, SERS was applied in situ on mushroom fruiting bodies to detect the presence of EGT. The SERS spectra revealed that the interaction of EGT with Ag nanoparticles underwent significant alterations at varying pH levels, primarily due to isomerization. These changes were associated with modifications in the aromaticity and ionization of the imidazole ring, driven by both metal adsorption and alkaline conditions. Our results indicated the formation of distinct tautomeric forms of the imidazole group, namely the thione and thiol forms, in aqueous solution and on the Ag surface, respectively. Furthermore, the EGT spectra at different concentrations suggested that ionization occurred at lower concentrations. Notably, the SERS spectra of the mushroom fruiting bodies were dominated by prominent bands attributable to EGT, as corroborated by the comparison with the EGT fungal extract and EGT standard. These findings underscore the utility of SERS spectroscopy as a rapid and effective tool for obtaining comprehensive molecular fingerprints, even directly from complex biological matrices such as mushroom fruiting bodies.https://www.mdpi.com/2227-9040/13/6/213imidazole ringtautomerizationnanoparticlesRamanpH effectcomplexation
spellingShingle Federico Puliga
Veronica Zuffi
Alessandra Zambonelli
Pavol Miškovský
Ornella Francioso
Santiago Sanchez-Cortes
Analysis of Ergothioneine Using Surface-Enhanced Raman Scattering: Detection in Mushrooms
Chemosensors
imidazole ring
tautomerization
nanoparticles
Raman
pH effect
complexation
title Analysis of Ergothioneine Using Surface-Enhanced Raman Scattering: Detection in Mushrooms
title_full Analysis of Ergothioneine Using Surface-Enhanced Raman Scattering: Detection in Mushrooms
title_fullStr Analysis of Ergothioneine Using Surface-Enhanced Raman Scattering: Detection in Mushrooms
title_full_unstemmed Analysis of Ergothioneine Using Surface-Enhanced Raman Scattering: Detection in Mushrooms
title_short Analysis of Ergothioneine Using Surface-Enhanced Raman Scattering: Detection in Mushrooms
title_sort analysis of ergothioneine using surface enhanced raman scattering detection in mushrooms
topic imidazole ring
tautomerization
nanoparticles
Raman
pH effect
complexation
url https://www.mdpi.com/2227-9040/13/6/213
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