Surface Enhanced Raman Scattering of Amino Acids Assisted by Gold Nanoparticles and Gd³⁺ Ions

Abstract

The surface enhanced raman scattering (SERS) signal from the l-tyrosine (tyr) molecule adsorbed on gold nanoparticles (Au-tyr) is compared with the SERS signal assisted by the presence of gadolinium ions (Gd(3+)) coordinated with the Au-tyr system. An enhancement factor of the SERS signal in the presence of Gd(3+) ions was ∼5 times higher than that produced by l-tyrosine adsorbed on gold nanoparticles. The enhancement of the SERS signal can be attributed to a corresponding increase in the local electric field due to the presence of Gd(3+) ions in the vicinity of a gold dimer configuration. This scenario was confirmed by solving numerically Maxwell equations, showing an increase of 1 order of magnitude in the local electric scattered field when the Gd(3+) ion is located in between a gold dimer compared with naked gold nanoparticles.

<p>Design and Synthesis of Gold-Gadolinium-Core-Shell Nanoparticles as Contrast Agent: a Smart Way to Future Nanomaterials for Nanomedicine Applications</p>

“…Raman spectroscopy and surface-enhanced Raman scattering were used to confirm the influence of Gd ions in Au–polymer nanoparticles. As described previously,23 the presence of Gd ions enhances the Raman signal of biomolecules (protein, natural polymer) capped onto gold nanoparticles (AuNPs).…”

“…The interaction energies were calculated using the ab initio plane-wave pseudopotential approach as implemented in the VASP code 22. The Perdew–Burke–Ernzerhof (PBE) functional23 was chosen to perform the periodic DFT calculations, with accuracy on the overall convergence tested elsewhere 24. The valence electrons were treated explicitly and their interactions with the ionic cores are described by the Projector Augmented-Wave method (PAW),28,37,38 which allows the use of a low-energy cutoff equal to 400 eV for the plane-wave basis.…”

“…The payload of gadolinium, particularly under its Gd(III) form in NP structures, has a notable effect in plenty of research fields from plasmonics to nanomedicine applications 21–23…”

The SERS effect in coordination chemistry

“…Lopez-Neira et al [271] observed that the SERS effect in L-tyrosine coated gold nanoparticles can be further enhanced by the coordination of Gd 3+ ions, after aggregation. The ~5 times enhancement promoted by the Gd 3+ ions was ascribed to the increase of the local electric field at the hot spot configuration.…”

Surface‐enhanced Raman scattering characteristics of CuO : Mn/Ag heterojunction probed by methyl orange: effect of Mn2+ doping

“…In SERS, a considerable enhancement of certain Raman bands is observed when the scattering molecules are adsorbed on rough metallic surfaces of nanoparticles of noble metals, e.g., Ag, Au and Cu. [1][2][3][4][5][6][7] The SERS effect is based mainly on two mechanisms: (1) a long-range electromagnetic (EM) effect and (2) a shortrange chemical (CHEM) effect/charge-transfer (CT) effect. The total enhancement is the result of both mechanisms (EM and CT).…”