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United States Department of Agriculture

Agricultural Research Service

Research Project: OPTICAL DETECTION OF FOOD SAFETY AND FOOD DEFENSE HAZARDS

Location: Quality and Safety Assessment Research Unit

Title: Stable silver/biopolymer hybrid plasmonic nanostructures for high performance surface enhanced raman scattering (SERS)

Authors
item Sundaram, Jaya
item Park, Bosoon
item Yongkuk, Kwon -

Submitted to: Journal of Nanoscience and Nanotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 28, 2013
Publication Date: July 24, 2013
Citation: Sundaram, J., Park, B., Yongkuk, K. 2013. Stable silver/biopolymer hybrid plasmonic nanostructures for high performance surface enhanced raman scattering (SERS). Journal of Nanoscience and Nanotechnology. 13(8):5382-5390.

Interpretive Summary: Raman spectroscopy gives light scattering to detect and characterize various properties of biological and non-biological materials. In practice Raman scattering is very weak and it needs to be enhanced to detect and characterize biological materials. To get enhanced Raman scattering (SERS) creation of patterned roughened surface substrates are needed. Several methods have been developed to make SERS substrates for biological applications. Most of the substrate preparation methods, however, need extensive procedures and expensive equipments, and the substrate are sometimes unstable. Therefore preparation of more stable substrate using simple procedure for biological sample detection is the current priority in SERS research. To achieve stable SERS substrate, a silver biopolymer nanoparticle was prepared in this work. This was used as biopolymer based metal substrate for SERS. Substrate was measured for its optical properties with hyperspectral microscopic imaging system, Transmission Electron Microscopic system, and UV-Visible spectrometer. Also their detection limits were observed using BPE (trans-1,2-bis(4-pyridyl)ethylene) and Rhodamine 6G.

Technical Abstract: Silver/biopolymer nanoparticles were prepared by adding 100 mg silver nitrate to 2% polyvinyl alcohol solution and reduced the silver nitrate into silver ion using 2 % trisodium citrate for high performance Surface Enhanced Raman Scattering (SERS) substrates. Optical properties of nanoparticle were analyzed using UV/VIS spectroscopy and hyperspectral imaging microscopy. Nanoparticle morphology was analyzed using transmission electron microscopy. UV/Vis absorption spectra of the silver biopolymer nanoparticles showed the plasmon resonance absorption band peak in the visible range at 460 nm. Sharp plasmon resonance peak was obtained from hyperspectral imaging spectral profile which indicates the homogeneous nature of the nanoparticles. Substrate reproducibility and repeatability were checked by measuring SERS signals of trans-1,2-bis(4-pyridyl)ethylene (BPE) and Rhodamine 6G. Substrate active surface uniformity was also checked through SERS mapping analysis. Substrate has good signal repeatability with less variation for both BPE and Rodamine 6G. Substrate reproducibility confirmed that spot-to-spot and batch-to-batch variability were quite small.

Last Modified: 4/19/2014
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