SERS Detection of Dopamine Using Label-Free Acridine Red as Molecular Probe in Reduced Graphene Oxide/Silver Nanotriangle Sol Substrate.

Yanghe Luo,Zhiliang Jiang,Aihui Liang,Lu Ma,Xinghui Zhang

doi:10.1186/s11671-015-0937-9

Yanghe Luo, Zhiliang Jiang + Show 3 more

Open Access

https://doi.org/10.1186/s11671-015-0937-9

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Abstract

The reduced graphene oxide/silver nanotriangle (rGO/AgNT) composite sol was prepared by the reduction of silver ions with sodium borohydride in the presence of H2O2 and sodium citrate. In the nanosol substrate, the molecular probe of acridine red (AR) exhibited a weak surface-enhanced Raman scattering (SERS) peak at 1506 cm−1 due to its interaction with the rGO of rGO/AgNT. Upon addition of dopamine (DA), the competitive adsorption between DA and AR with the rGO took place, and the AR molecules were adsorbed on the AgNT aggregates with a strong SERS peak at 1506 cm−1 that caused the SERS peak increase. The increased SERS intensity is linear to the DA concentration in the range of 2.5–500 μmol/L. This new analytical system was investigated by SERS, fluorescence, absorption, transmission electron microscope (TEM), and scanning electron microscope (SEM) techniques, and a SERS quantitative analysis method for DA was established, using AR as a label-free molecular probe.

Highlights

Noble metal nanoparticles have been widely employed in various fields such as catalysis, surface-enhanced Raman scattering, biomarkers, and thermal therapy due to their unique physical and chemical properties [1,2,3,4]
In the presence of a pH 6.0 PBS buffer solution containing 0.04 mol/L NaCl, when acridine red (AR) molecules were added into a rGO/A 43.1 μg/mL silver nanotriangle (AgNT) solution, AR could absorb on the rGO surface by π-π stacking and electrostatic interactions, but absorption on the AgNT aggregate surface was so poor showing a weak surface-enhanced Raman scattering (SERS) signal
The adsorption of DA molecules can lead to desorption of AR molecules from the rGO surface; the desorbed AR molecules adsorbed on the AgNT aggregates and showed a strong SERS signal

Summary

Introduction

Noble metal nanoparticles have been widely employed in various fields such as catalysis, surface-enhanced Raman scattering, biomarkers, and thermal therapy due to their unique physical and chemical properties [1,2,3,4]. Nanosilver has the advantages of a low-cost, higher molar extinction coefficient [5] and stronger surface-enhanced Raman scattering (SERS) effects [6]. The properties of metal nanoparticles depend strongly on the nanoparticles’ size and shape [8, 9]. Most of the methods need high-concentration surfactants as stabilizer that restrains SERS effect and pollutes the environment. It is significant to explore a simple, stable, environmentally friendly, and highly SERS-active AgNT sol preparation, combined with new nanomaterials

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