title: DNA-engineered chiroplasmonic heteropyramids for ultrasensitive detection of mercury ion.
abstract: In this study, plasmonic heteropyramids (HPs) made from two different sized gold nanoparticles (Au NPs) and five ssDNA sequences and their application for ultrasensitive detection of mercury ion (Hg(2+)) were demonstrated. Four ssDNA sequences were used as building blocks to form a pyramidal DNA frame, which contains a T-rich probe DNA at one vertex and three sulfhydryl groups modified with 10nm Au NPs at the other three vertices. Another T-rich DNA sequence was modified and attached to a 25 nm Au NP. In the presence of Hg(2+) ions, 25 nm Au NPs hybridized with pyramidal DNA frame to build the plasmonic HPs based on T-Hg(2+)-T interaction, which exhibits unprecedented circular dichroism (CD) signal in the visible region. Based on this mechanism, a simple, high sensitive and selective chiroplasmonic HPs-based probe was constructed and demonstrated for Hg(2+) ions detection. Under optimized conditions, Hg(2+) ions could be selectively detected in a concentration range from 1 to 500 pg mL(-1) with a limit of detection of 0.2 pg mL(-1), which is much lower than the strictest Hg(2+) safety requirement of 1 ng mL(-1) in water.
authors: National Center of Meat Quality & Safety Control, Nanjing Agricultural University, Nanjing 210095, China.
authors: Wenjing
authors: W
authors: Yan
authors: National Center of Meat Quality & Safety Control, Nanjing Agricultural University, Nanjing 210095, China.
authors: Yongli
authors: Y
authors: Wang
authors: Quality and Safety Assessment Research Unit, Agricultural Research Service, USDA, Athens, GA 30605, USA.
authors: Hong
authors: H
authors: Zhuang
authors: National Center of Meat Quality & Safety Control, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: nau_zjh@njau.edu.cn.
authors: Jianhao
authors: J
authors: Zhang
mesh_terms: D015374:Biosensing Techniques; D004277:DNA, Single-Stranded / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D007477:Ions / Q000737:chemistry / Q000302:isolation & purification*; D008628:Mercury / Q000737:chemistry / Q000302:isolation & purification*; D053768:Metal Nanoparticles / Q000737:chemistry
chemical_list: D004277:DNA, Single-Stranded; D007477:Ions; D006046:Gold; D008628:Mercury
keywords: Circular dichroism; Gold nanoparticles; Heteropyramids; Mercury ion