title: Synthesis, Optical Properties, and Multiplexed Raman Bio-Imaging of Surface Roughness-Controlled Nanobridged Nanogap Particles.
abstract: Plasmonic nanostructures are widely studied and used because of their useful size, shape, composition and assembled structure-based plasmonic properties. It is, however, highly challenging to precisely design, reproducibly synthesize and reliably utilize plasmonic nanostructures with enhanced optical properties. Here, we devise a facile synthetic method to generate Au surface roughness-controlled nanobridged nanogap particles (Au-RNNPs) with ultrasmall (≈1 nm) interior gap and tunable surface roughness in a highly controllable manner. Importantly, we found that particle surface roughness can be associated with and enhance the electromagnetic field inside the interior gap, and stronger nanogap-enhanced Raman scattering (NERS) signals can be generated from particles by increasing particle surface roughness. The finite-element method-based calculation results support and are matched well with the experimental results and suggest one needs to consider particle shape, nanogap and nanobridges simultaneously to understand and control the optical properties of this type of nanostructures. Finally, the potential of multiplexed Raman detection and imaging with RNNPs and the high-speed, high-resolution Raman bio-imaging of Au-RNNPs inside cells with a wide-field Raman imaging setup with liquid crystal tunable filter are demonstrated. Our results provide strategies and principles in designing and synthesizing plasmonically enhanced nanostructures and show potential for detecting and imaging Raman nanoprobes in a highly specific, sensitive and multiplexed manner.
authors.affiliation: Department of Chemistry, Seoul National University, Seoul, 08826, South Korea.
authors.forename: Jung-Hoon
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Chemistry, Seoul National University, Seoul, 08826, South Korea.
authors.forename: Jeong-Wook
authors.initials: JW
authors.lastname: Oh
authors.affiliation: Research Center for Convergence NanoRaman Technology (RC2NT), Korea Research Institute of Chemical Technology (KRICT), Daejeon, 34114, South Korea.
authors.forename: Sang Hwan
authors.initials: SH
authors.lastname: Nam
authors.affiliation: Department of Chemistry, Seoul National University, Seoul, 08826, South Korea.
authors.forename: Yeong Seok
authors.initials: YS
authors.lastname: Cha
authors.affiliation: Department of Chemistry, Seoul National University, Seoul, 08826, South Korea.
authors.forename: Gyeong-Hwan
authors.initials: GH
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Seoul National University, Seoul, 08826, South Korea.
authors.forename: Won-Kyu
authors.initials: WK
authors.lastname: Rhim
authors.affiliation: Research Center for Convergence NanoRaman Technology (RC2NT), Korea Research Institute of Chemical Technology (KRICT), Daejeon, 34114, South Korea.
authors.forename: Nam Hoon
authors.initials: NH
authors.lastname: Kim
authors.affiliation: Research Center for Convergence NanoRaman Technology (RC2NT), Korea Research Institute of Chemical Technology (KRICT), Daejeon, 34114, South Korea.
authors.forename: Jongwoo
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea.
authors.forename: Sang Woo
authors.initials: SW
authors.lastname: Han
authors.affiliation: Research Center for Convergence NanoRaman Technology (RC2NT), Korea Research Institute of Chemical Technology (KRICT), Daejeon, 34114, South Korea. ydsuh@krict.re.kr.|School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, South Korea. ydsuh@krict.re.kr.
authors.forename: Yung Doug
authors.initials: YD
authors.lastname: Suh
authors.affiliation: Department of Chemistry, Seoul National University, Seoul, 08826, South Korea. jmnam@snu.ac.kr.
authors.forename: Jwa-Min
authors.initials: JM
authors.lastname: Nam
mesh_terms: D045744:Cell Line, Tumor; D004247:DNA / Q000737:chemistry; D004574:Electromagnetic Fields; D006046:Gold / Q000737:chemistry; D006801:Humans; D019811:Hydroxylamine / Q000737:chemistry; D021621:Imaging, Three-Dimensional; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D055620:Optical Phenomena; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties
chemical_list: D019811:Hydroxylamine; D006046:Gold; D004247:DNA
keywords: Raman imaging; nanobridged nanogap particles; nanogap-enhanced Raman scattering; plasmonic nanoparticles; surface-enhanced Raman scattering