title: DNA-embedded Au-Ag core-shell nanoparticles assembled on silicon slides as a reliable SERS substrate.
abstract: This study aimed at developing a sensitive and reliable SERS substrate by assembling DNA-embedded Au-Ag core-shell nanoparticles (NPs) on silicon slides. First, a monolayer of well separated DNA-functionalized Au NPs (40 nm) was decorated on (3-aminopropyl)triethoxysilane modified silicon slides. The DNA-embedded Au-Ag core-shell NPs were assembled on the 40 nm Au-DNA NPs to form a core-satellite structure through DNA hybridization. Using 4-MBA as a Raman dye, the SERS performance of the substrates was evaluated after being cleaned by low oxygen and argon plasma. The Raman intensity of the assembly using DNA-embedded Au-Ag core-shell NPs was 8-10 times higher than the intensity of the assembly using Au NPs as satellites. In addition, the signal-to-noise ratio of the assembly was 2.6 times higher than that of a commercial substrate (Klarite™) when a 785 nm laser was used. The SERS enhancements of the assembled substrates were 2.2 to 2.8 times higher than the Klarite when an acquisition time of 5 s was used at an excitation wavelength of 633 nm. The assembled substrates also show a good spot-to-spot and substrate-to-substrate reproducibility at the excitation wavelengths of 633 and 785 nm. These results demonstrate that the fabrication process is simple and cost-effective for assembling DNA-embedded Au-Ag core-shell NPs on silicon slides that can be used as a reliable SERS substrate.
authors.affiliation: Division of Food Systems & Bioengineering, University of Missouri, Columbia, MO 65211-5160, USA. linme@missouri.edu.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Sha
authors.initials: S
authors.lastname: Zhang
authors.forename: Mengshi
authors.initials: M
authors.lastname: Lin
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D012825:Silicon / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*
chemical_list: D012834:Silver; D006046:Gold; D004247:DNA; D012825:Silicon