Development and characterization of a carbon electrode coated with DNA strands and XS-derived chitin-rich structural material for picomolar lead detection by DPV
Electrochimica Acta, cilt.576, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 576
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.electacta.2026.149625
- Dergi Adı: Electrochimica Acta
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: Electrochemical sensor, Guanin-rich DNA, Lead ion, Lichen, Xanthoparmelia stenophylla
- Ankara Üniversitesi Adresli: Evet
Özet
Lead (Pb2+) ion strongly binds to guanine-rich DNA sequences, particularly those forming G-quadruplex (GQ) structures, and affects the differential pulse voltammetry (DPV) oxidation signal of the guanine moiety. This interaction was utilized for lead detection in tap water. The surface of a screen-printed carbon electrode (SPCE) was coated with GQ; the resulting surface was then treated with an aqueous extract of Xanthoparmelia stenophylla (XS), whose chitin-rich structural components provide a chemically active, functional-group-rich interface that facilitates stable GQ immobilization and supports efficient Pb²⁺ recognition at the electrode surface. Guanine-rich DNA sequences form three-dimensional cage-like structures in which Pb2+ ions are trapped. The detection was based on a decrease in the guanine electrooxidation peak upon Pb2+ binding, attributed to stabilization of the GQ structure, which reduces the accessibility of guanine to direct electrochemical oxidation. The properties of the lichen-based material were systematically characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM), confirming a predominantly organic, functional-group-rich structural matrix containing minor inorganic constituents. The effects of XS content, GQ concentration, and interaction time were investigated to optimize the electrochemical response. Quantitative analysis of Pb2+ using the Pb2+–GQ-XS detection system yielded a linear range of 0.0050 to 0.70 nM and a detection limit of 2.4 pM. This platform offers a simple, low-cost, and label-free approach for the sensitive detection of trace Pb2+ in environmental water samples.