Document Detail


The chemical origin of enhanced signals from tip-enhanced Raman detection of functionalized nanoparticles.
MedLine Citation:
PMID:  23423552     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Here we present results that investigate the origins of signals observed in tip-enhanced Raman (TERS) measurements of functionalized nanoparticles. Surface enhanced Raman scattering (SERS) is known to give the largest enhancements in gap junctions. Similarly, gap-mode TERS also produces significant enhancements. The methodology developed here provides gap-mode like enhancements in TERS measurements without the need for a metal surface. Using a combination of aggregated nanoparticle SERS and TERS detection of functionalized nanoparticles, we assess the chemical origins of the observed peaks and show that molecules outside of gap junctions are also enhanced using our methodology. Our experiments use biotin and streptavidin as a model system for protein-ligand binding. Different size functionalized nanoparticles (20, 50, 80 nm) show changes in intensity in both SERS and TERS measurements. SERS measurements indicate that streptavidin has a larger Raman cross-section than biotin and is preferentially observed. The specific streptavidin peaks observed by TERS vary depending on whether streptavidin is attached to the nanoparticle and located in the gap or bound to the substrate surface. This methodology suggests a route to enhancing TERS signals associated with protein receptors in biological systems that cannot be isolated to a metallic surface.
Authors:
Hao Wang; Zachary D Schultz
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Analyst     Volume:  138     ISSN:  1364-5528     ISO Abbreviation:  Analyst     Publication Date:  2013 Jun 
Date Detail:
Created Date:  2013-05-07     Completed Date:  2013-12-27     Revised Date:  2014-06-10    
Medline Journal Info:
Nlm Unique ID:  0372652     Medline TA:  Analyst     Country:  England    
Other Details:
Languages:  eng     Pagination:  3150-7     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Gold / chemistry
Metal Nanoparticles / chemistry
Nanoparticles / chemistry*
Particle Size
Spectrum Analysis, Raman / methods*
Grant Support
ID/Acronym/Agency:
R00 RR024367/RR/NCRR NIH HHS; RR024367/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
7440-57-5/Gold
Comments/Corrections

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