A novel photoelectrochemical immunosensor by integration of nanobody and TiO2 nanotubes for sensitive detection of serum cystatin C

作者：Mi, Li; Wang, Pingyan; Yan, Junrong; Qian, Jing; Lu, Jusheng; Yu, Jiachao; Wang, Yuzhen; Liu, Hong; Zhu, Min; Wan, Yakun; Liu, Songqin^*

来源：Analytica Chimica Acta, 2016, 902: 107-114.

DOI：10.1016/j.aca.2015.11.007

• Naimbody
• Cystatin C
• Photoelectrochemical irnmunosensnl
• TiO2 nanotube arrays
• Covalence

Cystatin C (CysC) is a sensitive marker for the estimation of the glomerular filtration rate and the clinical diagnosis of different diseases. In this paper, CysC-specific nanobodies (Nbs) were isolated from a phage display nanobody library. A simple and sensitive photoelectrochemical immunosensor based on TiO2 nanotube arrays (TNAs) was proposed for the sensitive detection of CysC. The TiO2 nanotube arrays deposited by electrochemical anodization displayed a high and stable photocurrent response under irradiation. After coupling CysC-specific nanobocly to TNA (Nb/TNA), the proposed immunosensor for CysC can be utilized for tracking the photocurrent change of Nb/TNA caused by immunoreactions between CysC and the immobilized CysC-specific Nb. This allowed for the determination of CysC with a calibration range from 0.12 pM to 7.19 RM. The variation of the photocurrent was in a linear relationship with the logarithm of the CysC concentration in the range of 0.72 pM-3.6 nM. The immunosensor had a correlation coefficient of 0.97 and a detection limit of 0.14 pM at a signal-to-noise ratio of 3. The proposed immunosensor showed satisfactory intra- and inter-assay accuracy, high selectivity and good stability. As a result, this proposed strategy would offer a novel and simple approach for the detection of hnmunoreactions, provide new insights in popularizing the diagnosis of CysC, and extend the application of TiO2 nanotubes.

• 出版日期2016-1-1
• 单位中国科学院上海药物研究所; 东南大学