Abstract
Plasmonic anisotropic nanoparticles possess a number of hot spots on their surface due to the presence of sharp edges, tips or vertices, leading to a high electric field strength surrounding the nanostructures. In this paper, we explore different plasmonic nanostructures, including anisotropic gold nanostars (AuNSts) and spherical gold nanoparticles, in surface-enhanced infrared absorption spectroscopy (SEIRAS) in an attenuated total reflection (ATR) configuration. In our experiments, we observed up to 10-times enhancement of the infrared (IR) absorption of thioglycolic acid (TGA) and up to 2-times enhancement of signals for bovine serum albumin (BSA) protein on plasmonic nanostructure-based films deposited on a silicon (Si) internal reflection element (IRE) compared to bare Si IRE. The dependence of the observed enhancement on the amount of AuNSts present at the surface of the IRE has been demonstrated. Quantitative studies with both, TGA and BSA were performed, observing that the SEIRA signal can be correlated to the concentration of analyte molecules present within the evanescent field. The calibration curves in the presence of the AuNSts showed enhanced sensitivity as compared with the bare Si IRE. We finally compare efficiencies of anisotropic AuNSts and spherical citrate-capped and “bare” laser-synthesized gold nanoparticles as SEIRAS substrates for the detection of TGA and BSA. The signal obtained from AuNSts was at least 2 times higher for TGA molecules in comparison with spherical gold nanoparticles, which was explained by a more efficient generation of hot spots on anisotropic surface due to the presence of sharp edges, tips or vertices, leading to a high electric field strength surrounding the AuNSts.
| Original language | English |
|---|---|
| Pages (from-to) | 141-149 |
| Number of pages | 9 |
| Journal | Analytica Chimica Acta |
| Volume | 990 |
| DOIs | |
| Publication status | Published - 16 Oct 2017 |
| MoE publication type | A1 Journal article-refereed |
Funding
O. Bibikova acknowledges the support from Infotech Oulu Graduate School and International Graduate School in Molecular Medicine Ulm (IGradU) , the program “ Tissue Homeostasis: Development, Aging and Regeneration, TissueHome ”. A.I. López-Lorente thanks the Alexander von Humboldt Foundation for the award of a Postdoctoral Fellowship at the Institute of Analytical and Bioanalytical Chemistry (University of Ulm, Germany). Funding by the Horizon 2020 Framework Program of the European Union within the MSCA RISE Project TROPSENSE [grant number 645758 ] is greatly acknowledged. A. Popov acknowledges Academy of Finland for partial financial support [grant numbers 260321 , 290596 ]. This work was also partially supported by Government of Russian Federation [grant numbers 074-U01 ]. Finally, Yu. Ryabchikov and A. V. Kabashin acknowledge a support from LASERNANOCANCER [grant number PC201420 ]; GRAVITY projects of the ITMO “ Plan Cancer 2014–2019” INSERM program; AMIDEX project [grant number ANR-11-IDEX-0001-02 ] funded by the French “Investissements d’Avenir” French Government program .
Keywords
- FTIR spectroscopy
- Gold nanospheres
- Gold nanostars
- Plasmonic
- SEIRAS