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Compact Shielding of Graphene Monolayer Leads to Extraordinary SERS-Active Substrate with Large-Area Uniformity and Long-Term Stability.

Liu X, Wang J, Wu Y, Fan T, Xu Y, Tang L, Ying Y - Sci Rep (2015)

Bottom Line: Surface-enhanced Raman scattering (SERS) can significantly boost the inherently weak Raman scattering signal and provide detailed structural information and binding nature of the molecules on the surface.Besides, our fabrication strategy were also capable of fabricating the reproducible SERS sensing spots array, which may serve as a promising high-throughput or multi-analyte sensing platform.Taken together, the graphene-shielded SERS substrate holds great promise both in fundamental studies of the SERS effect and many practical fields.

View Article: PubMed Central - PubMed

Affiliation: College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China.

ABSTRACT
Surface-enhanced Raman scattering (SERS) can significantly boost the inherently weak Raman scattering signal and provide detailed structural information and binding nature of the molecules on the surface. Despite the long history of this technology, SERS has yet to become a sophisticated analytical tool in practical applications. A major obstacle is the absence of high-quality and stable SERS-active substrate. In this work, we report a monolayer graphene-shielded periodic metallic nanostructure as large-area uniform and long-term stable SERS substrate. The monolayer graphene acting as a corrosion barrier, not only greatly enhanced stability, but also endowed many new features to the substrate, such as alleviating the photo-induced damages and improving the detection sensitivity for certain analytes that are weakly adsorbed on the conventional metallic substrates. Besides, our fabrication strategy were also capable of fabricating the reproducible SERS sensing spots array, which may serve as a promising high-throughput or multi-analyte sensing platform. Taken together, the graphene-shielded SERS substrate holds great promise both in fundamental studies of the SERS effect and many practical fields.

No MeSH data available.


Related in: MedlinePlus

(a) SERS spectra after the substrates were immersed in (a) 10 ppm B(a)P and (b) 1 μM Cy3-labeled ssDNA in 0.1 M NaCl solution for 1 h and thoroughly washed by 0.1 M NaCl. The SERS spectra of B(a)p and Cy3 labeled ssDNA are also presented in the same figures (black).
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f7: (a) SERS spectra after the substrates were immersed in (a) 10 ppm B(a)P and (b) 1 μM Cy3-labeled ssDNA in 0.1 M NaCl solution for 1 h and thoroughly washed by 0.1 M NaCl. The SERS spectra of B(a)p and Cy3 labeled ssDNA are also presented in the same figures (black).

Mentions: Pervious work indicates SERS are effective in detecting molecules strongly adsorbed on the SERS substrate (pyridine, thiols and heterocyclic molecules, etc.), but for molecules with little affinity, SERS becomes rather ineffective39. Since graphene shows high affinity to the aromatic molecules and biomolecules that are weakly adsorbed on conventional metallic SERS substrate40, our graphene-shielded SERS substrate may help to solve the problem. We chose benzo(a)pyrene (B(a)P) and ssDNA (dye labeled) as models to study the enrichment effect of the substrate. B(a)P is a polycyclic aromatic hydrocarbon, a common byproduct of incomplete combustion or burning of organic components, which is classified as mutagen and potential carcinogen. Due to its high hydrophobicity and low affinity to the metallic surface, it is difficult to detect B(a)P via conventional SERS substrate4142. On the other hand, the specific recognition of DNA has been widely used in biosensing etc., and thus detection of DNA is also of great importance. Due to the inherently weak Raman signal of DNA, we used a dye labeled ssDNA instead. As shown in Fig. 7, the B(a)P or DNA exposed onto the graphene-coated substrate exhibited a stronger Raman signal than that of uncovered ones, indicating the existence of certain enrichment effect (perharps due to the π - π stacking interactions). It should be noted this effect is case-sensitive. But, a lower detection limit for certain analytes can be expected. More importantly, this effect may expand the applicability of SERS technique to molecules with little affinity to bare SERS substrates.


Compact Shielding of Graphene Monolayer Leads to Extraordinary SERS-Active Substrate with Large-Area Uniformity and Long-Term Stability.

Liu X, Wang J, Wu Y, Fan T, Xu Y, Tang L, Ying Y - Sci Rep (2015)

(a) SERS spectra after the substrates were immersed in (a) 10 ppm B(a)P and (b) 1 μM Cy3-labeled ssDNA in 0.1 M NaCl solution for 1 h and thoroughly washed by 0.1 M NaCl. The SERS spectra of B(a)p and Cy3 labeled ssDNA are also presented in the same figures (black).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663485&req=5

f7: (a) SERS spectra after the substrates were immersed in (a) 10 ppm B(a)P and (b) 1 μM Cy3-labeled ssDNA in 0.1 M NaCl solution for 1 h and thoroughly washed by 0.1 M NaCl. The SERS spectra of B(a)p and Cy3 labeled ssDNA are also presented in the same figures (black).
Mentions: Pervious work indicates SERS are effective in detecting molecules strongly adsorbed on the SERS substrate (pyridine, thiols and heterocyclic molecules, etc.), but for molecules with little affinity, SERS becomes rather ineffective39. Since graphene shows high affinity to the aromatic molecules and biomolecules that are weakly adsorbed on conventional metallic SERS substrate40, our graphene-shielded SERS substrate may help to solve the problem. We chose benzo(a)pyrene (B(a)P) and ssDNA (dye labeled) as models to study the enrichment effect of the substrate. B(a)P is a polycyclic aromatic hydrocarbon, a common byproduct of incomplete combustion or burning of organic components, which is classified as mutagen and potential carcinogen. Due to its high hydrophobicity and low affinity to the metallic surface, it is difficult to detect B(a)P via conventional SERS substrate4142. On the other hand, the specific recognition of DNA has been widely used in biosensing etc., and thus detection of DNA is also of great importance. Due to the inherently weak Raman signal of DNA, we used a dye labeled ssDNA instead. As shown in Fig. 7, the B(a)P or DNA exposed onto the graphene-coated substrate exhibited a stronger Raman signal than that of uncovered ones, indicating the existence of certain enrichment effect (perharps due to the π - π stacking interactions). It should be noted this effect is case-sensitive. But, a lower detection limit for certain analytes can be expected. More importantly, this effect may expand the applicability of SERS technique to molecules with little affinity to bare SERS substrates.

Bottom Line: Surface-enhanced Raman scattering (SERS) can significantly boost the inherently weak Raman scattering signal and provide detailed structural information and binding nature of the molecules on the surface.Besides, our fabrication strategy were also capable of fabricating the reproducible SERS sensing spots array, which may serve as a promising high-throughput or multi-analyte sensing platform.Taken together, the graphene-shielded SERS substrate holds great promise both in fundamental studies of the SERS effect and many practical fields.

View Article: PubMed Central - PubMed

Affiliation: College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China.

ABSTRACT
Surface-enhanced Raman scattering (SERS) can significantly boost the inherently weak Raman scattering signal and provide detailed structural information and binding nature of the molecules on the surface. Despite the long history of this technology, SERS has yet to become a sophisticated analytical tool in practical applications. A major obstacle is the absence of high-quality and stable SERS-active substrate. In this work, we report a monolayer graphene-shielded periodic metallic nanostructure as large-area uniform and long-term stable SERS substrate. The monolayer graphene acting as a corrosion barrier, not only greatly enhanced stability, but also endowed many new features to the substrate, such as alleviating the photo-induced damages and improving the detection sensitivity for certain analytes that are weakly adsorbed on the conventional metallic substrates. Besides, our fabrication strategy were also capable of fabricating the reproducible SERS sensing spots array, which may serve as a promising high-throughput or multi-analyte sensing platform. Taken together, the graphene-shielded SERS substrate holds great promise both in fundamental studies of the SERS effect and many practical fields.

No MeSH data available.


Related in: MedlinePlus