title: Quantitative enhanced Raman scattering of labeled DNA from gold and silver nanoparticles.
abstract: Surface-enhanced resonance Raman scattering (SERRS) from silver nanoparticles using 514.5-nm excitation has been shown to offer huge potential for applications in highly sensitive multiplexed DNA assays. If the technique is to be applied to real biological samples and integrated with other methods, then the use of gold nanoparticles and longer wavelengths of excitation are desirable. The data presented here demonstrate that dye-labeled oligonucleotide sequences can be directly detected by SERRS using gold nanoparticles in a quantitative manner for the first time. The performance of gold and silver nanoparticles as SERRS substrates was assessed using 514.5-, 632.8-, and 785-nm excitation and a range of 13 commercially available dye-labeled oligonucleotides. The quantitative response allowed the limit of detection to be determined for each case and demonstrates that the technique is highly effective, sensitive, and versatile. The possibility of excitation at multiple wavelengths further enhances the multiplexing potential of the technique. The importance of effectively combining the optical properties of the nanoparticle and the dye label is demonstrated. For example, at 632.8-nm excitation, the dye BODIPY TR-X and gold nanoparticles make a strong SERRS combination with very little background fluorescence. This study allows the choice of nanoparticle and dye label for particular experimental setups, and significantly expands the applicability of enhanced Raman scattering for use in many disciplines.
authors.affiliation: Centre for Molecular Nanometrology, WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Stokes
authors.forename: Alexandra
authors.initials: A
authors.lastname: Macaskill
authors.forename: P Johan
authors.initials: PJ
authors.lastname: Lundahl
authors.forename: W Ewen
authors.initials: WE
authors.lastname: Smith
authors.forename: Karen
authors.initials: K
authors.lastname: Faulds
authors.forename: Duncan
authors.initials: D
authors.lastname: Graham
mesh_terms: D020099:Coated Materials, Biocompatible / Q000737:chemistry; D003460:Crystallization / Q000379:methods; D004247:DNA / Q000737:chemistry* / Q000235:genetics* / Q000648:ultrastructure; D006046:Gold / Q000737:chemistry*; D008027:Light; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D010316:Particle Size; D012542:Scattering, Radiation; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties
chemical_list: D020099:Coated Materials, Biocompatible; D046911:Macromolecular Substances; D012834:Silver; D006046:Gold; D004247:DNA