Document Detail

Tuning and Maximizing the Single-Molecule Surface-Enhanced Raman Scattering from DNA-Tethered Nanodumbbells.
MedLine Citation:
PMID:  23036132     Owner:  NLM     Status:  Publisher    
Obtaining a strong and reproducible surface-enhanced Raman scattering (SERS) signal with a narrow distribution of the high SERS enhancement factor (EF) values from the plasmonic nanostructures is critical for better understanding and practical use of the single-molecule SERS (SMSERS) nanoprobes. In this regard, the systematic and thorough studies about the relationships between single-molecule SERS intensity, EF distribution over many particles, inter-particle distance, particle size/shape/composition and excitation laser wavelength are needed. Here, we extensively studied these relationships using the single-particle AFM-correlated Raman measurement method with two different single-DNA-tethered Au-Ag core-shell nanodumbbell (GSND) designs with engineerable nanogap - the GSND-I with various inter-particle nanogaps from ~4.8 nm to <1 nm or with no gap and the GSND-II with the fixed inter-particle gap size and varying particle size for various size of GSND-II particles from a 23 nm-30 nm pair to a 50 nm-60 nm pair. From the GSND-I probes, we learned that synthesizing <1 nm gap is a key to obtain strong SMSERS signals with a narrow EF value distribution. Importantly, in the case of the GSND-I with <1 nm inter-particle gap, an EF value of as high as 5.9×1013 (average value = 1.8×1013) was obtained and the EF values of analyzed particles were narrowly distributed between 1.9×1012 and 5.9×1013. In the case of the GSND-II probes, a combination of >50 nm Au cores and 514.5 nm laser wavelength that matches well with Ag shell generated stronger SMSERS signals with a more narrow EF distribution than <50 nm Au cores with 514.5 nm laser or the GSND-II structures with 632.8 nm laser. Our results show the usefulness and flexibility of these GSND structures in studying and obtaining SMSERS structures with a narrow distribution of high EF values and the GSNDs are promising SERS probes with highly sensitive and quantitative detection capability when optimally designed.
Jung-Hoon Lee; Jwa-Min Nam; Ki-Seok Jeon; Dong-Kwon Lim; Hyoki Kim; Sunghoon Kwon; Haemi Lee; Yung Doug Suh
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-10-4
Journal Detail:
Title:  ACS nano     Volume:  -     ISSN:  1936-086X     ISO Abbreviation:  ACS Nano     Publication Date:  2012 Oct 
Date Detail:
Created Date:  2012-10-5     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101313589     Medline TA:  ACS Nano     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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