title: Ultrasensitive electrochemical sensor for Hg(2+) by using hybridization chain reaction coupled with Ag@Au core-shell nanoparticles.
abstract: A novel electrochemical biosensor for Hg(2+) detection was reported by using DNA-based hybridization chain reaction (HCR) coupled with positively charged Ag@Au core-shell nanoparticles ((+)Ag@Au CSNPs) amplification. To construct the sensor, capture probe (CP ) was firstly immobilized onto the surface of glass carbon electrode (GCE). In the presence of Hg(2+), the sandwiched complex can be formed between the immobilized CP on the electrode surface and the detection probe (DP) modified on the gold nanoparticles (AuNPs) based on T-Hg(2+)-T coordination chemistry. The carried DP then opened two ferrocene (Fc) modified hairpin DNA (H1 and H2) in sequence and propagated the happen of HCR to form a nicked double-helix. Numerous Fc molecules were formed on the neighboring probe and produced an obvious electrochemical signal. Moreover, (+)Ag@Au CSNPs were assembly onto such dsDNA polymers as electrochemical signal enhancer. Under optimal conditions, such sensor presents good electrochemical responses for Hg(2+) detection with a detection limit of 3.6 pM. Importantly, the methodology has high selectivity for Hg(2+) detection.
authors: School of Life Science, Jiangsu Normal University, Xuzhou 221116, PR China.
authors: Zongbing
authors: Z
authors: Li
authors: School of Life Science, Jiangsu Normal University, Xuzhou 221116, PR China. Electronic address: mxm0107@jsnu.edu.cn.
authors: Xiangmin
authors: X
authors: Miao
authors: School of Life Science, Jiangsu Normal University, Xuzhou 221116, PR China.
authors: Ke
authors: K
authors: Xing
authors: School of Life Science, Jiangsu Normal University, Xuzhou 221116, PR China.
authors: Xue
authors: X
authors: Peng
authors: School of Life Science, Jiangsu Normal University, Xuzhou 221116, PR China. Electronic address: ahzhu@jsnu.edu.cn.
authors: Aihua
authors: A
authors: Zhu
authors: School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China. Electronic address: cesllsh@mail.sysu.edu.cn.
authors: Liansheng
authors: L
authors: Ling
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002413:Cations, Divalent / Q000032:analysis; D004247:DNA / Q000737:chemistry; D055664:Electrochemical Techniques / Q000379:methods*; D005296:Ferrous Compounds / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D008628:Mercury / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry*; D000075163:Metallocenes; D009693:Nucleic Acid Hybridization / Q000379:methods; D012834:Silver / Q000737:chemistry*; D014867:Water / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D002413:Cations, Divalent; D005296:Ferrous Compounds; D000075163:Metallocenes; D014874:Water Pollutants, Chemical; D014867:Water; D012834:Silver; D006046:Gold; D004247:DNA; D008628:Mercury; C004998:ferrocene
keywords: Electrochemical sensor; Hg(2+) detection; Hybridization chain reaction; Positively charged Ag@Au core-shell nanoparticles