One-step synthesis of gold nanoflowers of tunable size and absorption wavelength in the red & deep red range for SERS spectroscopy

Mathias Pacaud; Katel Hervé-Aubert; Martin Soucé; Alaa Abdelrahman Makki; Franck Bonnier; Amir Fahmi; Alexey Feofanov; Igor Chourpa

doi:10.1016/j.saa.2019.117502

One-step synthesis of gold nanoflowers of tunable size and absorption wavelength in the red & deep red range for SERS spectroscopy

Spectrochim Acta A Mol Biomol Spectrosc. 2020 Jan 15:225:117502. doi: 10.1016/j.saa.2019.117502. Epub 2019 Aug 31.

Authors

Mathias Pacaud¹, Katel Hervé-Aubert², Martin Soucé², Alaa Abdelrahman Makki², Franck Bonnier², Amir Fahmi³, Alexey Feofanov⁴, Igor Chourpa⁵

Affiliations

¹ EA6295 Nanomédicaments et Nanosondes, Université de Tours, Tours, France; Faculty Technology&Bionics, Rhein-Waal University of Applied Sciences, Kleve, Germany.
² EA6295 Nanomédicaments et Nanosondes, Université de Tours, Tours, France.
³ Faculty Technology&Bionics, Rhein-Waal University of Applied Sciences, Kleve, Germany.
⁴ Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia; Biological Faculty, Lomonosov Moscow State University, Moscow, Russia.
⁵ EA6295 Nanomédicaments et Nanosondes, Université de Tours, Tours, France. Electronic address: Igor.chourpa@univ-tours.fr.

PMID: 31499392
DOI: 10.1016/j.saa.2019.117502

Abstract

We describe a novel protocol for a one-step, seed-less, organic solvent- and surfactant-free synthesis of optically dense aqueous colloids of gold nanoflowers (AuNF), with tunable absorption wavelength between 620 and 800 nm. We demonstrate that simple variation of the ratio of two reagents allows the plasmonic band position to be tuned to any desired wavelength ± 5 nm, namely to those of the laser sources commonly used for SERS spectroscopy. The AuNF size distribution was sufficiently narrow, comparable to that known with seed-mediated synthesis. The AuNF have been validated as efficient aggregation-free substrates for surface-enhanced Raman scattering (SERS) spectroscopy using two common fluorescent dyes, Nile Blue and Crystal Violet, both thiol-free. Their fluorescence was quenched and SERS signal intensity was a linear function of the dye concentration, from nanomolar to micromolar range. Easy to prepare and to use, these AuNF appear as a particularly user-friendly and efficient way to obtain plasmonic substrates for SERS in the red and deep red spectral range.

Keywords: Gold nanoflower AuNF; Localised surface plasmon resonance (LSPR) band; Surface-enhanced Raman scattering (SERS) spectroscopy.