A triply amplified electrochemical lead(II) sensor by using a DNAzyme and via formation of a DNA-gold nanoparticle network induced by a catalytic hairpin assembly

• Published in: Mikrochimica acta (1966) 2019-08, Vol.186 (8), p.559, Article 559
• Main Authors: Song, Xiaolei, Wang, Yu, Liu, Su, Zhang, Xue, Wang, Jingfeng, Wang, Haiwang, Zhang, Fenfen, Yu, Jinghua, Huang, Jiadong
• Format: Article
• Language: English
• Subjects: Amplification; Analytical Chemistry; Assembly; Biosensing Techniques; Biosensors; Catalysis; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; DNA; DNA, Catalytic - chemistry; Drinking Water - analysis; Electrochemical analysis; Electrochemical Techniques; Enzymes; Gold; Gold - chemistry; Lead; Lead - analysis; Lead - chemistry; Metal Nanoparticles - chemistry; Microengineering; Nanochemistry; Nanoparticles; Nanotechnology; Original Paper; Recycling; Sensors; Substrates; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - chemistry
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-019-3612-5

An amplified electrochemical biosensing scheme is described for lead(II) ions. It is making use of DNAzyme-assisted target recycling and catalytic hairpin assembly (CHA). The hairpin strand (substrate probe for the Pb 2+ -based DNAzyme; referred to as SP) is composed of trigger probe (TP) and a capture probe 1 attached to gold nanoparticles (AuNP). In the presence of the enzyme probe that partially hybridizes with SP, the introduction of Pb 2+ triggers target recycling and drives the highly amplified translation of target Pb(II) to TP. The CHA reaction is further initiated by TP. The modified AuNP act as the connecting unit, and this leads to the formation of a 3D DNA-AuNP network on the electrode (which is the third amplification step). It can bind the positively charged redox mediator RuHex via electrostatic interaction for electrochemical detection. This biosensor has a low detection limit (95 pM) and any analytical range that covers the 100 pM to 5 μM Pb(II) concentration range. It is selective over other divalent metal ions. It was applied to the determination of Pb 2+ in spiked real-world samples. Graphical abstract Schematic presentation of the electrochemical biosensor. The triply amplified electrochemical assay is based on the use of DNAzyme-assisted target recycling with catalytic hairpin assembly (CHA) reaction for sensitive and selective determination of lead ion (Pb 2+ ). AuNP: gold nanoparticles; SP: substrate probe; EP: enzyme probe.