title: Au NPs-enhanced surface plasmon resonance for sensitive detection of mercury(II) ions.
abstract: We reported a sensitive surface plasmon resonance (SPR) sensor for the detection of Hg(2+) in aqueous solution by using a thymine (T)-rich, mercury-specific oligonucleotide (MSO) probe and gold nanoparticles (Au NPs)-based signal amplification. The MSO probe was first immobilized on gold film through formation of Au-S bond between DNA and gold film. In the presence of Hg(2+), the MSO probe captured free Hg(2+) in aqueous media via the Hg(2+)-mediated coordination of T-Hg(2+)-T base pairs. This direct immobilization strategy led to a detection limit of 0.3 microM of Hg(2+). In order to improve the sensitivity, part complementary DNA (PCS)-modified Au NPs labels were employed to amplify SPR signals. We demonstrated that this Au NPs-based sensing strategy resulted in a detection limit down to 5 nM of Hg(2+), brings about an amplification factor of two orders of magnitude. This Au NPs-based Hg(2+) sensor also exhibited excellent selectivity over a spectrum of interference metal ions. Taking advantage of the high amplifying characteristic of Au NPs and the specificity of MSO to Hg(2+) recognition, we developed here a SPR sensor for specific Hg(2+) detection with high sensitivity.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Du
authors.forename: Chaogui
authors.initials: C
authors.lastname: Chen
authors.forename: Bingling
authors.initials: B
authors.lastname: Li
authors.forename: Ming
authors.initials: M
authors.lastname: Zhou
authors.forename: Shaojun
authors.initials: S
authors.lastname: Dong
mesh_terms: D001483:Base Sequence; D006046:Gold; D057230:Limit of Detection; D008628:Mercury / Q000032:analysis*; D053768:Metal Nanoparticles; D015345:Oligonucleotide Probes / Q000235:genetics; D020349:Surface Plasmon Resonance / Q000295:instrumentation / Q000379:methods*
chemical_list: D015345:Oligonucleotide Probes; D006046:Gold; D008628:Mercury