Niu Y, Luo G, Xie H, Zhuang Y, Wu X, Li G, Sun W. Photoelectrochemical aptasensor for lead(II) by exploiting the CdS nanoparticle-assisted photoactivity of TiO
2 nanoparticles and by using the quercetin-copper(II) complex as the DNA intercalator.
Mikrochim Acta 2019;
186:826. [PMID:
31754803 DOI:
10.1007/s00604-019-3951-2]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 10/17/2019] [Indexed: 01/27/2023]
Abstract
A photoelectrochemical (PEC) aptasensor for Pb(II) detection is described. A nanocomposite consisting of CdS (2.5 μm) and TiO2 nanoparticles (10 nm) was used as a photoactive material, and gold nanochains (Au NCs) as the support for immobilization of the Pb(II)-binding aptamer. The quercetin-copper(II) complex was further employed as the intercalator for the improvement of the photoactivity by embedding it into dsDNA. In the presence of Pb(II), a Pb(II)-stabilized G-quadruplex was formed between Pb(II) and DNA S1. This is accompanied by unwinding of the dsDNA and the release of the quercetin-copper(II) complex from the surface of the sensor. This results in a decrease of the photocurrent that drops linearly from 5.0 × 10-12 to 1.0 × 10-8 mol·L-1 Pb(II) concentration range with a detection limit of 1.6 × 10-12 mol·L-1. The method was applied to the determination of Pb(II) in various samples and gave satisfactory results. Graphical abstractA photoelectrochemical aptasensor was fabricated for the detection of Pb(II) based on CdS-TiO2 nanocomposite modified indium tin oxide (ITO) electrode. Gold nanochains (AuNCs) were used as anchor to immobilize the aptamers S1 and S2 that form a double helix structure by DNA hybridization. After embedding of quercetin-copper(II) complex as intercalator and electron donor, the concentrations of Pb(II) were determined by the changes of photocurrents.
Collapse