Citrate-reduced silver nanoparticles (Ag-NPs) are used extensively for surface-enhanced Raman scattering (SERS) studies, but are typically found to aggregate using an aggregation agent. This study is aimed at developing a simple, stable, and reproducible aggregated method for Ag-NPs without any aggregation agents in aqueous solutions. The aggregation is induced by the process of centrifugation, water washing and ultrasonication. A mechanism based on the nonuniform distribution of capping ligands is proposed to account for the aggregated structure formation. UV-Vis-NIR extinction spectra and TEM allowed us to identify the existence of Ag-NPs aggregation. Further, due to the polydisperse mixture of Ag-NPs (20~65 nm) used in the present work, Ag-NPs are aggregated closely, which contribute to the observation of low-concentration SERS from the residual citrate layer or even the single-molecule SERS of R6Gon aggregation. After the evaporation of droplet of Ag-NPs aggregation on the Si substrate, citrate or R6Gcould also be detected but with marked redor blue-shifts.
References
[1]
R. K. Chang and T. E. Furtak, “Surface-Enhanced Raman Scattering,” Plenum Press, New York, 1982.
doi:10.1007/978-1-4615-9257-0
[2]
K. Kneipp, H. Kneipp, I. Itzkan, R. R. Dasari and M. S. Feld, “Ultrasensitive Chemical Analysis by Raman Spectroscopy Chemical Reviews,” Vol. 99, No. 10, 1999, pp. 2957-2975.
http://shaker.umh.es/docencia/aesma/review.Raman.Spctroscopy.1999.pdf
[3]
G. C. Schatz and P. R. Van Duyne, “Electromagnetic Mechanism of Surface-Enhanced Spectroscopy,” In: J. M. Chalmers and P. R. Griffiths, Eds., Handbook of Vibrat ional Spectroscopy Vol. 1, John Wiley & Sons Ltd., Chichester, 2002, p. 759.
[4]
R. Aroca, “Surface-Enhanced Vibrational Spectroscopy,” John Wiley & Sons Ltd., Chichester, 2006.
doi:10.1002/9780470035641
[5]
K. Kneipp, M. Moskovits and H. Kneipp, “Surface-Enhanced Raman Scattering,” Springer-Verlag, Berlin, 2006.
doi:10.1007/3-540-33567-6
[6]
S. Lee, S. Kim, J. Choo, S. Y. Shin, Y. H. Lee, H. Y. Choi, S. Ha, K. Kang and C. H. Oh, “Biological Imaging of HEK293 Cells Expressing PLCγ1 Using Surface-En-hanced Raman Microscopy,” Analytical Chemistry, Vol. 79, No. 3, 2007, pp. 916-922. doi:10.1021/ac061246a
[7]
C. Ruan, W. Wang and B. Gu, “Detection of Alkaline Phosphatase Using Surface-Enhanced Raman Spectroscopy,” Analytical Chemistry, Vol. 78, No. 10, 2006, pp. 3379-3384. doi:10.1021/ac0522106
[8]
X. X. Han, G. G. Huang, B. Zhao and Y. Ozaki, “Label-Free Highly Sensitive Detection of Proteins in Aqueous Solutions Using Surface-Enhanced Raman Scatting,” Analytical Chemistry, Vol. 81, No. 9, 2009, pp. 33293333. doi:10.1021/ac900395x
[9]
X. X. Han, B. Zhao, Y. Ozaki, “Surface-enhanced Raman scattering for protein detection,” Analytical Bioanalytical Chemistry, Vol. 394, No. 7, 2009, pp. 1719-1727.
doi:10.1007/s00216-009-2702-3
[10]
S. E. J. Bell and N. M. S. Sirimuthu, “Suface-Enhanced Raman Spectroscopy (SERS) for Sub-Micromolar Detection of DNA/RNA Mononucleotides,” Journal of the American Chemical Society, Vol. 128, No. 49, 2006, pp. 15580-15581. doi:10.1021/ja066263w
[11]
W. Yuan, H. P. Ho, R. K. Y. Lee, S. K. Kong, “Sur FaceEnhanced Raman Scattering Biosensor for DNA Detection on Nanoparticle Island Substrates” Applied Optics, Vol. 48, No. 22, 2009, pp. 4329-4337.
doi:10.1364/AO.48.004329
[12]
Y. C. Cao, R. Jin and C. A. Mirkin, “Nanoparticles with Raman Spectroscopic Fingerprints for DNA and RNA Detection,” Science, Vol. 297, No. 5586, 2009, pp. 15361540. doi:10.1126/science.297.5586.1536
[13]
H. W. Han, X. L. Yan, R. X. Dong, G. Ban and K. Li, “Analysis of Serum from Type II Diabetes Mellitus and Diabetic Complication Using Surface-Enhanced Raman Spectra (SERS),” Applied Physics B, Vol. 94, No. 4, 2009, pp. 667-672. doi:10.1007/s00340-008-3299-5
[14]
T. A. Alexander, “Development of Methodology Based on Commercialized SERS-Active Substrates for Rapid Discrimination of Poxviridae Virions,” Analytical Chemistry, Vol. 80, No. 8, 2008, pp. 2817-2825.
doi:10.1021/ac702464w
[15]
M. Kahraman, A. I. Zamaleeva, R. F. Fakhrullin and M. Culha, “Characterization of Yeast Species Using SurfaceEnhanced Raman Scattering Volume,” Applied Spectroscopy, Vol. 63, No. 11, 2009, pp. 1276-1282.
doi:10.1366/000370209789806849
[16]
H. Wang, C. S. Levin and N. J. Halas, “Nanosphere Arrays with Controlled Sub-10-nm Gaps as Surface-Enhanced Raman Spectroscopy Substrates,” Journal of the American Chemical Society, Vol. 127, No. 43, 2005, pp. 14992-14993. doi:10.1021/ja055633y
[17]
Y. Maruyama and M. Futamata, “Anion Induced SERS Activation and Quenching for R6G Adsorbed on Ag Nanoparticles,” Chemical Physics Letters, Vol. 448, No. 1-3, 2007, pp. 93-98. doi:10.1016/j.cplett.2007.09.056
[18]
P. J. Schuck, D. P. Fromm, A. Sundaramurthy, G. S. Kino and W. E. Moerner, “Improving the Mismatch between Light and Nanoscale Objects with Gold Bowtie Nanoantennas,” Physical Review Letters, Vol. 94 , No. 1, 2005, pp. 17402. doi:10.1103/PhysRevLett.94.017402
[19]
R. Kodiyath, T. A. Papadopoulos, J. Wang, Z. A. Combs, H. Li, R. J. C. Brown, J. Bredas and V. V. Tsukruk, “Silver-Decorated Cylindrical Nanopores: Combining the Third Dimension with Chemical Enhancement for Efficient Trace Chemical Detection with SERS,” Journal of Physical Chemistry C, Vol. 116, No. 26, 2012, pp. 1391713927. doi:10.1021/jp300902u
[20]
W. Ren, Y. X. Fang and E. K. Wang, “A Binary Functional Substrate for Enrichment and Ultrasensitive SERS Spectroscopic Detection of Folic Acid Using Graphene Oxide/Ag Nanoparticle Hybrids,” ACS Nano, Vol. 5, No. 8, 2011, pp. 6425-6433. doi:10.1021/nn201606r
[21]
S. E. J. Bell and N. M. S. Sirimuthu, “Surface-Enhanced Raman Spectroscopy as a Probe of Competitive Binding by Anions to Citrate-Reduced Silver Colloids,” Journal of Physical Chemistry A, Vol. 109, No. 33, 2005, pp. 7405-7410. doi:10.1021/jp052184f
[22]
S. E. J. Bell, J. N. Mackle and N. M. S. Sirimuthu, “Quantitative Surface-Enhanced Raman Spectroscopy of Dipicolinic Acid-Towards Rapid Anthrax Endospore Detection,” Analyst, Vol. 130, No. 4, 2005, pp. 545-549.
doi:10.1039/b415290e
[23]
S. E. J. Bell and N. M. S. Sirimuthu, “Surface-Enhanced Raman Spectroscopy (SERS) for Sub-Micromolar Detection of DNA/RNA Mononucleotides,” Journal of the American Chemical Society, Vol. 128, No. 49, 2006, pp. 15580-15581. doi:10.1021/ja066263w
[24]
F. R. Ma, K. Liu, Y. Zhang and S. Pan, “A Novel Silver Colloid as Substrate for Detection of Single-Molecular Level of R6G,” The Journal of Light Scattering, Vol. 19, No. 1, 2007, p. 11.
[25]
C. H. Munro, W. E. Smith, M. Garner, J. Clarkson and P. C. White, “Characterization of the Surface of a CitrateReduced Colloid Optimized for Use as a Substrate for Surface-Enhanced Resonance Raman Scattting,” Lanmuir, Vol. 11, No. 10, 1995, pp. 3712-3720.
doi:10.1021/la00010a021
[26]
M. Hong, L. L. Wu, L. F. Tian and J. Zhu, “Controlled Assembly of Au, Ag, and Pt Nanoparticles with Chitosan,” Vol. 15, No. 24, 2009, pp. 5935-5941.
[27]
L. L. Wu, C. S. Shi, L. F. Tian and J. Zhu, “A One-Pot Method to Prepare Gold Nanoparticle Chains with Chitosan,” Journal of Physical Chemistry C, Vol. 112, No. 2, 2008, pp. 319-323. doi:10.1021/jp076733o
[28]
M. Futamata and Y. Maruyama, “LSP Spectral Changes Correlating with SERS Activation and Quenching for R6G on Immobilized Ag Nanoparticles,” Applied Physics B, Vol. 93, No. 1, 2008, pp. 117-130.
doi:10.1007/s00340-008-3179-z
[29]
S．Schlucker, “Surface Enhanced Raman Spectroscopy: Analytical, Biophysical and Life Science Applications,” Wiley-VCH Verlag GmbH & Co., Weinheim, 2011.
[30]
H. Wang, C. S. Levin and N. J. Halas, “Nanosphere Arrays with Controlled Sub-10-nm Gaps as Surface-Enhanced Raman Spectroscopy Substrates,” Journal of the American Chemical Society, Vol. 127, No. 43, 2005, pp. 14992-14993. doi:10.1021/ja055633y
[31]
S. Nie and S. R. Emory, “Probing Single Molecules and Single Nanoparticles by Surface-Enhanced Raman Scattering,” Science, Vol. 275, No. 5303, 1997, pp. 11021106. doi:10.1126/science.275.5303.1102
[32]
K. Kneipp, Y. Wang, H. Kneipp, L. T. Perelman, I. Itzkan, R. R. Dasari and M. S. Feld, “Single Molecule Detection Using Surface-Enhanced Raman Scattering (SERS),” Physical Review Letters, Vol. 78, No. 9, 1997, pp. 16671670. doi:10.1103/PhysRevLett.78.1667
[33]
J. Polleux, N. Pinna, M. Antonietti and M. Niederberger, “Ligand-Directed Assembly of Preformed Titania Nanocrystals into Highly Anisotropic Nanostrutures,” Advanced Materials, Vol. 16, No. 5, 2004, pp. 436-439.
doi:10.1002/adma.200306251
[34]
X. X. Han, Y. Kitahama, T. Itoh, C. X. Wang, B. Zhao, Y. Ozaki, “Protein-Mediated Sandwich Strategy for Surface-Enhanced Raman Scattering: Application to Versatile Protein Detection,” Analytical Chemistry, Vol. 81, No. 9, 2009, pp. 3350-3355. doi:10.1021/ac802553a
[35]
M. Kahraman, I. Sur and M. Culha, “Label-Free Detection of Proteins from Self-Assembled Protein-Silver Nanoparticle Structures Using Surface-Enhanced Raman Scattering,” Analytical Chemistry, Vol. 82, No. 18, 2010, pp. 7596-7602. doi:10.1021/ac101720s
