title: Highly uniform and reproducible surface-enhanced Raman scattering from DNA-tailorable nanoparticles with 1-nm interior gap.
abstract: An ideal surface-enhanced Raman scattering (SERS) nanostructure for sensing and imaging applications should induce a high signal enhancement, generate a reproducible and uniform response, and should be easy to synthesize. Many SERS-active nanostructures have been investigated, but they suffer from poor reproducibility of the SERS-active sites, and the wide distribution of their enhancement factor values results in an unquantifiable SERS signal. Here, we show that DNA on gold nanoparticles facilitates the formation of well-defined gold nanobridged nanogap particles (Au-NNP) that generate a highly stable and reproducible SERS signal. The uniform and hollow gap (∼1 nm) between the gold core and gold shell can be precisely loaded with a quantifiable amount of Raman dyes. SERS signals generated by Au-NNPs showed a linear dependence on probe concentration (R(2) > 0.98) and were sensitive down to 10 fM concentrations. Single-particle nano-Raman mapping analysis revealed that >90% of Au-NNPs had enhancement factors greater than 1.0 × 10(8), which is sufficient for single-molecule detection, and the values were narrowly distributed between 1.0 × 10(8) and 5.0 × 10(9).
authors.affiliation: Department of Chemistry, Seoul National University, Seoul, 151-747, South Korea.
authors.forename: Dong-Kwon
authors.initials: DK
authors.lastname: Lim
authors.forename: Ki-Seok
authors.initials: KS
authors.lastname: Jeon
authors.forename: Jae-Ho
authors.initials: JH
authors.lastname: Hwang
authors.forename: Hyoki
authors.initials: H
authors.lastname: Kim
authors.forename: Sunghoon
authors.initials: S
authors.lastname: Kwon
authors.forename: Yung Doug
authors.initials: YD
authors.lastname: Suh
authors.forename: Jwa-Min
authors.initials: JM
authors.lastname: Nam
mesh_terms: D004247:DNA / Q000737:chemistry*; D020342:Finite Element Analysis; D006046:Gold; D053768:Metal Nanoparticles / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D010316:Particle Size; D013056:Spectrophotometry, Ultraviolet; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D006046:Gold; D004247:DNA