Colloidal europium nanoparticles via a solvated metal atom dispersion approach and their surface enhanced Raman scattering studies

• Published in: Journal of colloid and interface science 2016-08, Vol.476, p.177-183
• Main Authors: Urumese, Ancila, Jenjeti, Ramesh Naidu, Sampath, S., Jagirdar, Balaji R.
• Format: Article
• Language: English
• Subjects: 4-ATP; Biomolecules; Colloids - chemical synthesis; Colloids - chemistry; Cytochrome-c; Dispersion; Europium; Europium - chemistry; Europium nanoparticles; Excitation; Hemoglobin; Lanthanides; Metal Nanoparticles - chemistry; Nanoparticles; Particle Size; Raman scattering; Rare earth metals; SERS; SMAD; Solubility; Spectrum Analysis, Raman; Surface Plasmon Resonance; Surface Properties
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2016.05.015

[Display omitted] •Synthesis of europium nanoparticles, the most reactive of lanthanide elements in the size regime of 4–5nm.•First experimental investigation of a rare-earth nanoparticles as SERS substrate.•First time demonstrating the interaction of europium nanoparticles with biomolecules like Hb and Cyt-c. Chemistry of lanthanide metals in their zerovalent state at the nanoscale remains unexplored due to the high chemical reactivity and difficulty in synthesizing nanoparticles by conventional reduction methods. In the present study, europium(0) nanoparticles, the most reactive of all the rare earth metals have been synthesized by solvated metal atom dispersion (SMAD) method using hexadecyl amine as the capping agent. The as-prepared europium nanoparticles show surface Plasmon resonance (SPR) band in the visible region of the electromagnetic spectrum. This lead to the investigation of its surface enhanced Raman scattering (SERS) using visible light excitation source. The SERS activity of europium nanoparticles has been followed using 4-aminothiophenol and biologically important molecules such as hemoglobin and Cyt-c as the analytes. This is the first example of lanthanide metal nanoparticles as SERS substrate which can possibly be extended to other rare-earth metals. Since hemoglobin absorbs in the visible region, the use of visible light excitation source leads to surface enhanced resonance Raman spectroscopy (SERRS). The interaction of biomolecules with Eu(0) has been followed using FT-IR and UV–visible spectroscopy techniques. The results indicate that there is no major irreversible change in the structure of biomolecules upon interaction with europium nanoparticles.