Dual Signal Amplification Electrochemical Biosensor for Lead Cation

Abstract

Herein, a sensitive electrochemical Pb2+ sensor was developed which based on DNA‐functionalized Au nanoparticles(AuNPs) and nanocomposite modified electrode. The DNA‐functionalized AuNPs includes two types of DNA, namely a Pb2+‐mediated DNAzyme comprising a biotin labeled‐enzyme DNA and a substrate strand DNA with a typical stem‐loop structure, and a ferrocene‐labeled linear signal DNA. Without Pb2+, the hairpin loop impeded biotin binding to avidin on the electrode. However,when the goal Pb2+ exists, the substratum strand was divided into two fragments that lead to the enzyme strand was substratumed on the electrode and biotin was admited by avidin, bringing about DNA‐functionalized AuNP(AuNPs) deposition on the electrode surface.The differential pulse voltammetry (DPV) was used to measure electrochemical response signals connect to signal DNA.For the amplification characters of the DNA‐functionalized AuNPs and nanocomposite, the electrochemical detection signal of Pb2+ was greatly improved and revealed high specificity. Under optimum conditions, the resultant biosensor bringed out a high sensitivity and selectivity for the determination of Pb2+. The proposed method was able to detect as low as picomolar Pb2+ concentrations.

A fluorescent DNAzyme-based biosensor for the detection of lead ions using carbon quantum dots prepared from grapefruit peel

“…16 In the presence of metal ions, DNAzyme catalyzes the cleavage of the substrate strand by the enzyme strand. 17 This feature has been exploited to build many sensors such as colorimetric, 18 fluorescent, 19 electrochemical, 20 surface plasmon resonance-based, 21 and microcantilever-based sensors. 22 Because of its advantages of fast response time and simple operation, fluorescent sensors have attracted much attention.…”

Label-free hairpin-like aptamer and EIS-based practical, biostable sensor for acetamiprid detection

“…And it has many outstanding advantages of inconsiderable toxicity and immunogenicity, inexpensiveness, feasible production, high thermal and chemical stability compared to antibody [ 22 , 23 ]. And aptamer-based electrochemical sensors have been widely applied to detect toxic pollutants [ 24 ], such as pesticides [ 25 ], heavy metals [ 26 ], antibiotics [ 27 , 28 ] and toxins [ 29 , 30 ].…”