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Published on: January 15, 2012
Surface enhanced infrared absorption spectroscopy based on gold nanostars and spherical nanoparticles
Olga Bibikova1, Julian Haas2, Ángela I López-Lorente2
1Optoelectronics and Measurement Techniques Research Unit, University of Oulu, 90014 Oulu, Finland; Institute of Analytical and Bioanalytical Chemistry, Ulm University, 89081 Ulm, Germany; Art Photonics GmbH, 12489 Berlin, Germany; Research-Educational Institute of Optics and Biophotonics, Saratov National Research State University, 410012 Saratov, Russia.
Anisotropic gold nanostars significantly enhance infrared absorption signals for molecules like thioglycolic acid and bovine serum albumin. These plasmonic nanoparticles offer improved sensitivity for detecting analytes in surface-enhanced infrared absorption spectroscopy.
Area of Science:
- Plasmonics and Nanotechnology
- Spectroscopy
- Biomolecular Detection
Background:
- Plasmonic anisotropic nanoparticles exhibit localized 'hot spots' due to sharp features, enhancing electric fields.
- Surface-enhanced infrared absorption (SEIRA) spectroscopy utilizes plasmonic substrates to amplify weak IR signals.
- Gold nanostructures are effective plasmonic materials for enhancing spectroscopic techniques.
Purpose of the Study:
- To investigate the efficacy of anisotropic gold nanostars (AuNSts) as SEIRA substrates.
- To compare the performance of AuNSts with spherical gold nanoparticles for SEIRA.
- To evaluate the enhanced sensitivity for detecting thioglycolic acid (TGA) and bovine serum albumin (BSA).
Main Methods:
- Fabrication of plasmonic films using anisotropic gold nanostars (AuNSts) and spherical gold nanoparticles on silicon internal reflection elements (IREs).
- Surface-enhanced infrared absorption (SEIRA) spectroscopy in an attenuated total reflection (ATR) configuration.
- Quantitative analysis of TGA and BSA detection using calibration curves and signal enhancement measurements.
Main Results:
- AuNSts demonstrated up to 10-times enhancement for thioglycolic acid (TGA) IR absorption and up to 2-times enhancement for bovine serum albumin (BSA) signals compared to bare silicon IRE.
- The SEIRA signal intensity correlated with the concentration of analyte molecules within the evanescent field.
- Anisotropic AuNSts provided at least 2 times higher signals for TGA compared to spherical gold nanoparticles, attributed to efficient hot spot generation.
Conclusions:
- Anisotropic gold nanostars are highly effective SEIRA substrates, significantly enhancing IR absorption signals.
- AuNSts offer improved sensitivity for quantitative analysis of analytes like TGA and BSA.
- The enhanced performance of AuNSts is due to their unique surface morphology and efficient hot spot generation.
