Journal
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
Volume 410, Issue 23, Pages 5879-5887Publisher
SPRINGER HEIDELBERG
DOI: 10.1007/s00216-018-1204-6
Keywords
Pb2+ detection; Electrochemical biosensor; Gold nanoparticles; G-quadruplex
Funding
- Natural Science Foundation of Jiangsu Province [BK20131406, BK20130917]
- Six Talent Peaks Project in Jiangsu Province [2015-JY-009]
- State Key Laboratory of Bio-organic and Natural Products Chemistry, CAS [SKLBNPC15429]
- National Science Foundation of China [21225626, 21506101]
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We present a novel simple strategy for the detection of Pb2+ based on G-quadruplex DNA and gold nanoparticles. First, gold nanoparticles were chemically adsorbed onto the surface of a thiol-modified gold electrode. Subsequently, the substrate DNA1 was adsorbed onto the surfaces of the gold nanoparticles via thiol-gold bonds, so that the complementary guanine-rich DNA2 could be hybridized to the gold electrode in sequence. [Ru(NH3)(6)](3+) (RuHex), which can be electrostatically adsorbed onto the anionic phosphate of DNA, served as an electrochemical probe. The presence of Pb2+ can induce DNA2 to form a stable G-quadruplex and fall off the gold electrode. The amount of RuHex remaining on the electrode surface was determined by electrochemical chronocoulometry (CC). The prepared biosensor showed high sensitivity for Pb2+ with a linear range with respect to ln(c(Pb2+)) from 0.01 to 200 nM and a low detection limit of 0.0042 nM under optimal conditions. Because of the high selectivity of the Pb2+-specific DNA2, the designed biosensor also showed low false-positive signal rates with other metal ions in real-world examples. Therefore, this strategy has the potential for practical application in environmental monitoring.
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