title: Nanogap-engineerable Raman-active nanodumbbells for single-molecule detection.
abstract: Surface-enhanced Raman scattering (SERS)-based signal amplification and detection methods using plasmonic nanostructures have been widely investigated for imaging and sensing applications. However, SERS-based molecule detection strategies have not been practically useful because there is no straightforward method to synthesize and characterize highly sensitive SERS-active nanostructures with sufficiently high yield and efficiency, which results in an extremely low cross-section area in Raman sensing. Here, we report a high-yield synthetic method for SERS-active gold-silver core-shell nanodumbbells, where the gap between two nanoparticles and the Raman-dye position and environment can be engineered on the nanoscale. Atomic-force-microscope-correlated nano-Raman measurements of individual dumbbell structures demonstrate that Raman signals can be repeatedly detected from single-DNA-tethered nanodumbbells. These programmed nanostructure fabrication and single-DNA detection strategies open avenues for the high-yield synthesis of optically active smart nanoparticles and structurally reproducible nanostructure-based single-molecule detection and bioassays.
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: Hyung Min
authors.initials: HM
authors.lastname: Kim
authors.forename: Jwa-Min
authors.initials: JM
authors.lastname: Nam
authors.forename: Yung Doug
authors.initials: YD
authors.lastname: Suh
mesh_terms: D001681:Biological Assay; D020134:Catalytic Domain; D004247:DNA / Q000737:chemistry; D019281:Dimerization; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D018625:Microscopy, Atomic Force / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D009841:Oligonucleotides / Q000737:chemistry; D015203:Reproducibility of Results; D012834:Silver / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties; D013696:Temperature
chemical_list: D009841:Oligonucleotides; D012834:Silver; D006046:Gold; D004247:DNA