Special Section on Climate Change and Water Resources: Climate Nonstationarity and Water Resources Management

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 apramer 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 similar to 4, in situ, atomic force microscopy imaging showed the mean height of the Au NP-bearing aptamer to decrease by similar to 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