Development of a novel electrochemical DNA biosensor based on elongated hexagonal-pyramid CdS and poly-isonicotinic acid composite film

• Published in: Biosensors & bioelectronics Vol. 60; pp. 167 - 174
• Main Authors: Zheng, Delun, Wang, Qingxiang, Gao, Feng, Wang, Qinghua, Qiu, Weiwei, Gao, Fei
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.10.2014; Elsevier
• Subjects: Biological and medical sciences; Biosensing Techniques - instrumentation; Biosensors; Biotechnology; Cadmium Compounds - chemistry; Conductometry - instrumentation; DNA - analysis; DNA - genetics; DNA biosensor; Electrochemical polymerization; Elongated hexagonal-pyramid CdS; Equipment Design; Equipment Failure Analysis; Fundamental and applied biological sciences. Psychology; Isonicotinic acid; Isonicotinic Acids - chemistry; Methods. Procedures. Technologies; Oligonucleotide Array Sequence Analysis - instrumentation; Reproducibility of Results; Selenium Compounds - chemistry; Sensitivity and Specificity; Sequence Analysis, DNA - instrumentation; Various methods and equipments; Elongated hexagonal-pyramid CdS; Electrochemical polymerization; DNA biosensor; Isonicotinic acid; Composite film; Biosensor; DNA; Electrochemistry
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2014.04.011

Three CdS materials with different shapes (i.e., irregular, rod-like, and elongated hexagonal-pyramid) were hydrothermally synthesized through controlling the molar ratio of Cd2+ to thiourea. Electrochemical experiments showed that the elongated hexagonal-pyramid CdS (eh-CdS) modified on glassy carbon electrode (GCE) had the higher electrical conductivity than the other two forms. Then the eh-CdS modified GCE was further modified with a layer of poly-isonicotinic acid (PIA) through electro-polymerization in IA solution to enhance the stability and functionality of the interface. The layer-by-layer modification process was characterized by atomic force microscopy and electrochemistry. Then 5′-amino functionalized DNA was immobilized on the electrode surface through coupling with the carboxylic groups derived from PIA-eh-CdS composite film. The hybridization performance of the developed biosensor was evaluated using methylene blue as redox indicator, and the results showed that the peak currents of methylene blue varied with target concentrations in a wide linear range from 1.0×10−14M to 1.0×10−9M with a low detection limit of 3.9×10−15M. The biosensor also showed high stability and good discrimination ability to the one-base, three-base mismatched and non-complementary sequence. •Three kinds of CdS with different shapes were synthesized.•The elongated hexagonal-pyramid CdS (eh-CdS) presented the highest conductivity.•A DNA biosensor was constructed using eh-CdS/poly-isonicotinic acid (PIA) as a platform.•Wide linear range (10fM–1.0nM) and low detection limit (3.9fM) were achieved.