Label-Free Photoelectrochemical Immunosensor for Neutrophil Gelatinase-Associated Lipocalin Based on the Use of Nanobodies

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• 作者：Henan Li ; Yawen Mu ; Junrong Yan ; Dongmei Cui ; Weijun Ou ; Yakun Wan ; Songqin Liu
• 刊名：Analytical Chemistry
• 出版年：2015
• 出版时间：February 3, 2015
• 年：2015
• 卷：87
• 期：3
• 页码：2007-2015
• 全文大小：536K
• ISSN：1520-6882

文摘

Acute renal failure (ARF) represents a very important and potentially devastating disorder in clinical nephrology. Neutrophil gelatinase-associated lipocalin (NGAL) is an early biomarker for ARF in a wide range of different disease processes, which is frequently detected in clinical diagnosis. Herein, we present a label-free and sensitive photoelectrochemical (PEC) immunosensor for NGAL by utilizing a biotinylated anti-NGAL Nanobody (Nb) orientedly immobilized to streptavidin-coated cobalt 2,9,16,23-tetraaminophthalocyanine (CoPc)-sensitized TiO₂ electrode. The Nb was biotinylated at the C-terminus, which is situated at the opposite site of the antigen binding region. Using highly oriented Nb as receptor molecules, a label-free PEC immunosensor for NGAL was developed by monitoring the changes in the photocurrent signals of the electrode resulting from immunoreaction. Immobilization of Nb to streptavidin-coated CoPc-sensitized TiO₂ electrode surface provides high binding capacity to NGAL; thus, it can lead to a high sensitivity. The limit of detection (LOD) of the proposed immunosensor has been significantly lowered to 0.6 pg mL^鈥?. This proposed immunosensor reveals high specificity to detect NGAL, with acceptable intra-assay precision and excellent stability. In addition, the present work provides a new approach to design Nb-based PEC immunosensor and increases versatility of Nbs.