title: A new approach to solution-phase gold seeding for SERS substrates.
abstract: Surface-enhanced Raman scattering (SERS) vastly improves signal-to-noise ratios as compared to traditional Raman scattering, making sensitive assays based upon Raman scattering a reality. However, preparation of highly stable SERS-active gold substrates requires complicated and expensive methodologies and instrumentation. Here, a general and completely solution-phase, seed-based approach is introduced, which is capable of producing gold films for SERS applications on a variety of substrates, not requiring surface modification or functionalization. SERS enhancement factors of ≈10(7) were observed. Moreover, solution-phase gold film deposition on highly complex surfaces, such as protein-coated bioassays, is demonstrated for the first time. Protein bioassays coated with such SERS-active gold films are combined with bioconjugated single-walled carbon nanotube Raman labels, affording highly sensitive detection of the cancer biomarker, carcinoembryonic antigen in serum, with a limit of detection of ≈5 fM (1 pg mL(-1) ).
authors.affiliation: Department of Chemistry, Stanford University, 380 Roth Way, Stanford, CA 94305, USA.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Tabakman
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Chen
authors.forename: Hernan Sanchez
authors.initials: HS
authors.lastname: Casalongue
authors.forename: Hailiang
authors.initials: H
authors.lastname: Wang
authors.forename: Hongjie
authors.initials: H
authors.lastname: Dai
mesh_terms: D001681:Biological Assay / Q000379:methods; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*
chemical_list: D006046:Gold