title: An amplified surface plasmon resonance "turn-on" sensor for mercury ion using gold nanoparticles.
abstract: Inorganic mercury ion (Hg(2+)) has been shown to coordinate to DNA duplexes that feature thymine-thymine (T-T) base pair mismatches. This observation suggests that an Hg(2+)-induced conformational change in a single-stranded DNA molecule can be used to detect aqueous Hg(2+). Here, we have developed an analytical method using surface plasmon resonance (SPR) to develop a highly selective and sensitive detection technique for Hg(2+) that takes advantage of T-Hg(2+)-T coordination chemistry. The general concept used in this approach is that the "turn-on" reaction of a hairpin probe via coordination of Hg(2+) by the T-T base pair results in a substantial increase in the SPR response, followed by specific hybridization with a gold nanoparticle probe to amplify the sensor performance. Meanwhile, the limit of detection is 1 nM, which is lower than other recently developed techniques. A linear correlation is observed between the measured SPR reflectivity and the logarithm of the Hg(2+) concentration over the concentration range of 5-5000 nM. Additionally, the SPR system provides high selectivity for Hg(2+) in the presence of other divalent metal ions up to micromolar concentration levels. The proposed approach is also successfully utilized for the determination of Hg(2+) in water samples.
authors: Institute of Biomedical Engineering, National Taiwan University, Taipei 10617, Taiwan.
authors: Chia-Chen
authors: CC
authors: Chang
authors: Shenhsiung
authors: S
authors: Lin
authors: Shih-Chung
authors: SC
authors: Wei
authors: Chen-Yu
authors: CY
authors: Chen
authors: Chii-Wann
authors: CW
authors: Lin
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004784:Environmental Monitoring / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007477:Ions; D008628:Mercury / Q000032:analysis*; D008832:Microchemistry / Q000295:instrumentation*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D007477:Ions; D014874:Water Pollutants, Chemical; D008628:Mercury