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

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• 作者：Jing-Xi Wang ; Ying Zhuo ; Ying Zhou ; Hai-Jun Wang ; Ruo Yuan ; Ya-Qin Chai
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：May 25, 2016
• 年：2016
• 卷：8
• 期：20
• 页码：12968-12975
• 全文大小：495K
• 年卷期：0
• ISSN：1944-8252

文摘

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.