title: Aptamer-mediated surface-enhanced Raman spectroscopy intensity amplification.
abstract: A bifunctional adenosine-sensitive double-stranded DNA aptamer was used to create and control a surface-enhanced Raman spectroscopy (SERS) hot spot between a bulk Au surface and a gold nanoparticle (Au NP) attached to the aptamer via a biotin-avidin linkage. The Au NP was decorated with 4-aminobenzenethiol (4-ABT), a Raman reporter molecule. In the presence of adenosine, the target molecule, the SERS spectrum of 4-ABT increased in intensity by (concentration-dependent) factors as large as ∼4; in situ, atomic force microscopy imaging showed the mean height of the Au NP-bearing aptamer to decrease by ∼5 nm consistent with the observed SERS intensity change. Because the aptamer's geometrical change is induced by one or two molecules, while the resulting SERS intensity changes involve many reporter molecules residing in the modified hot spot, the aptamer amplifies the SERS effect.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, United States.
authors.forename: Nam Hoon
authors.initials: NH
authors.lastname: Kim
authors.forename: Seung Joon
authors.initials: SJ
authors.lastname: Lee
authors.forename: Martin
authors.initials: M
authors.lastname: Moskovits
mesh_terms: D000241:Adenosine / Q000032:analysis; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods; D006046:Gold / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D053758:Nanoparticles / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013425:Sulfanilic Acids / Q000737:chemistry; D013499:Surface Properties
chemical_list: D052157:Aptamers, Nucleotide; D013425:Sulfanilic Acids; C100016:4-sulfanilic acid; D006046:Gold; D000241:Adenosine