title: Bimetallic gold-silver nanoplate array as a highly active SERS substrate for detection of streptavidin/biotin assemblies.
abstract: The silver-modified gold nanoplate arrays as bimetallic surface-enhanced Raman scattering (SERS) substrates were optimized for the surface-enhanced Raman detection of streptavidin/biotin monolayer assemblies. The bimetallic gold-silver nanoplate arrays were fabricated by coating silver nanoparticles uniformly on the gold nanoplate arrays. Depending on silver nanoparticle coating, the localized surface plasmon resonance (LSPR) peak of the bimetallic gold-silver nanoplate arrays blue-shifted and broadened significantly. The common probe molecule, Niel Blue A sulfate (NBA) was used for testing the SERS activity of the bimetallic gold-silver nanoplate arrays. The SERS intensity increased with the silver nanoparticle coating, due to a large number of hot spots and nanoparticle interfaces. The platforms were tested against a monolayer of streptavidin functionalized over the bimetallic gold-silver nanoplate arrays showing that good quality spectra could be acquired with a short acquisition time. The supramolecular interaction between streptavidin (strep) and biotin showed subsequent modification of Raman spectra that implied a change of the secondary structure of the host biomolecule. And the detection concentration for biotin by this method was as low as 1.0 nM. The enhanced SERS performance of such bimetallic gold-silver nanoplate arrays could spur further interest in the integration of highly sensitive biosensors for rapid, nondestructive, and quantitative bioanalysis, particularly in microfluidics.
authors.affiliation: State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, PR China.
authors.forename: Liyan
authors.initials: L
authors.lastname: Bi
authors.forename: Jian
authors.initials: J
authors.lastname: Dong
authors.forename: Wei
authors.initials: W
authors.lastname: Xie
authors.forename: Wenbo
authors.initials: W
authors.lastname: Lu
authors.forename: Wei
authors.initials: W
authors.lastname: Tong
authors.forename: Lin
authors.initials: L
authors.lastname: Tao
authors.forename: Weiping
authors.initials: W
authors.lastname: Qian
mesh_terms: D001710:Biotin / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D019809:Streptavidin / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D020349:Surface Plasmon Resonance; D013499:Surface Properties
chemical_list: D012834:Silver; D001710:Biotin; D006046:Gold; D019809:Streptavidin
keywords: Bimetallic gold–silver nanoplate array; Localized surface plasmon resonance (LSPR); Streptavidin/biotin assemblies; Surface enhanced Raman scattering (SERS)