首页|Triple signal amplification electrochemical sensing platform for Hg2+ in water without direct modification of the working electrode

Triple signal amplification electrochemical sensing platform for Hg2+ in water without direct modification of the working electrode

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An ultrasensitive electrochemical biosensor to detect trace Hg2+in environmental samples was developed utilizing nanogold-decorated magnetic reduced graphene oxide(MrGO-AuNPs),exonuclease Ⅲ-assisted target cycle(Exo Ⅲ-ATC)and hybridization chain reaction(HCR)synergistic triple signal amplification.The MrGO-AuNPs is a superior carrier for capture DNA(cDNA)and acts as magnetic media for automatic separation and adsorption.This innovative utilization of the magnetism and improved sensing efficiency obviates the need for direct modification and repeated polishing of the working electrode.Additionally,the three DNA hairpins(cDNA,methylene blue(MB)labeled HP1 and HP2)further contribute to biosensor specificity and selectivity.When cDNA captures Hg2+,it activates Exo Ⅲ-ATC due to the formation of a sticky end in the cDNA stem via thymine-Hg2+-thymidine(T-Hg2+-T),this leads to the hydrolysis of self-folded cDNA by Exo Ⅲ-ATC to form"key"DNA(kDNA).The kDNA subsequently initiates HCR,resulting in massive super-sandwich structures(kDNA-[HP1/HP2]n)carrying signaling molecules on MrGO-AuNPs,and this overall structure serves as a signal probe(SP).Leveraging magnetic adsorption,the SP was automatically adsorbed onto the magneto-glass carbon electrode(MGCE),generating an amplified signal.This biosensor's detection limit(LOD)was 3.14 pmol/L,far below the limit of 10 nmol/L for mercury in drinking water set by the US EPA.The biosensor also showed excellent selectivity when challenged by interfering ions,and the results of its application in actual samples indicate that it has good potential for practical applications in environmental monitoring.

Electrochemical sensingHg2+AmplificationGrapheneHybridization chain reactionExonuclease Ⅲ

Liuyin Hu、Jiahua Cui、Tao Lu、Yalin Wang、Jinping Jia

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School of Environmental Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China

School of Chemistry and Chemical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China

International Copper Association,Ltd.,Shanghai 200020,China

Key Research and Development Program of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of China

2018YFC0213400217370022197611922176126

2024

10.1007/s11783-024-1850-1

环境科学与工程前沿
高等教育出版社

环境科学与工程前沿

影响因子：0.545
ISSN：2095-2201
年,卷(期)：2024.18(7)