Ceria Doped Zinc Oxide Nanoflowers Enhanced Luminol-Based Electrochemiluminescence Immunosensor for Amyloid‑β Detection

• Published in: ACS applied materials & interfaces Vol. 8; no. 20; pp. 12968 - 12975
• Main Authors: Wang, Jing-Xi, Zhuo, Ying, Zhou, Ying, Wang, Hai-Jun, Yuan, Ruo, Chai, Ya-Qin
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 25.05.2016
• Subjects: amyloid-β; electrochemiluminescence; immunosensor; ceria doped zinc oxide nanoflowers; luminol
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.6b00021

In this work, ceria doped ZnO nanomaterials with flower-structure (Ce:ZONFs) were prepared to construct a luminol-based electrochemiluminescence (ECL) immunosensor for amyloid-β protein (Aβ) detection. Herein, carboxyl groups (−COOH) covered Ce:ZONFs were synthesized by a green method with lysine as reductant. After that, Ce:ZONFs-based ECL nanocomposite was prepared by combining the luminophore of luminol and Ce:ZONFs via amidation and physical absorption. Luminol modified on Ce:ZONFs surface could generate a strong ECL signal under the assistance of reactive oxygen species (ROSs) (such as OH• and O2 •–), which were produced by a catalytic reaction between Ce:ZONFs and H2O2. It was worth noticing that a quick Ce4+ ↔ Ce3+ reaction in this doped material could increase the rate of electron transfer to realize the signal amplification. Subsequently, the luminol functionalized Ce:ZONFs (Ce:ZONFs-Lum) were covered by secondary antibody (Ab2) and glucose oxidase (GOD), respectively, to construct a novel Ab2 bioconjugate (Ab2-GOD@Ce:ZONFs-Lum). The wire-structured silver–cysteine complex (AgCys NWs) with a large number of −COOH, which was synthesized by AgNO3 and l-cysteine, was used as substrate of the immunosensor to capture the primary antibody (Ab1). Under the optimal conditions, this proposed ECL immunosensor had exhibited high sensitivity for Aβ detection with a wide linear range from 80 fg/mL to 100 ng/mL and an ultralow detection limit of 52 fg/mL. Meanwhile, this biosensor had good specificity for Aβ, indicating that the provided strategy had a promising potential in the detection of Aβ.