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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Quality and Safety Assessment Research Unit » Research » Publications at this Location » Publication #314785
Title: DNA-engineered chiroplasmonic heteropyramids for ultrasensitive detection of mercuryion

Author
item YAN, WENJING - Nanjing Agricultural University
item WANG, YONGLI - Nanjing Agricultural University
item Zhuang, Hong
item ZHANG, JIANHAO - Nanjing Agricultural University

Submitted to: Biosensors and Bioelectronics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/12/2015
Publication Date: 1/13/2015
Citation: Yan, W., Wang, Y., Zhuang, H., Zhuang, J. 2015. DNA-engineered chiroplasmonic heteropyramids for ultrasensitive detection of mercuryion. Biosensors and Bioelectronics. 68:516-520.

Interpretive Summary: Hg2+ ions are highly toxic heavy metal ions that are produced from the industrial wastes and natural activities. The ions can be transformed into methyl mercuric compounds, concentrate through biological cycles, and finally cause a series of diseases, such as pneumonia, enteritis and bronchitis. Mercury pollution is widely found in tap water and food and has been one of food safety concerns to consumers in the entire world. The objective of this study was to develop a simple, high sensitive and selective-DNA based method to detect Hg2+ ion content in tap water. Results show that under optimized conditions, Hg2+ ions could be selectively detected using this method 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 Hg2+ safety requirement of 1ng mL-1in water, and its sensitivity toward Hg ions was approximately 9 times higher than those of Mg ions, Cd ions, and Cu ions, and 30 times higher than those of Fe3+ ions, Fe2+ ions, Pb ions,, Mn ions, Zn ions, and Ca ions, demonstrating that this DNA-based method (DNA-engineered heterogeneous nanoparticle assembly) can be used for the sensitive and selective detection of Hg2+ ions in tap water.

Technical 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 (Hg2+) were demonstrated. Four ssDNA sequences were used as building blocks to form apyramidal DNA frame, which contains a T-rich probe DNA at one vertex and three sulfhydryl groups modified with10 nm Au NPs at the other three vertices. Another T-rich DNA sequence was modified and attached to a 25nm Au NP. In the presence of Hg2+ ions, 25 nm Au NP shybridized with pyramidal DNA frame to build the plasmonic HPs based on T–Hg2+–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 Hg2+ ions detection. Under optimized conditions, Hg2+ 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 Hg2+ safety requirement of 1ng mL-1in water.