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A Photoelectrochemical Immunosensor Based on Au‐Doped TiO 2 Nanotube Arrays for the Detection of α‐Synuclein

2010; Wiley; Volume: 16; Issue: 48 Linguagem: Inglês

10.1002/chem.201001654

1521-3765

Yarui An, Linlin Tang, Xiaoli Jiang, Hua Chen, Meicheng Yang, Litong Jin, Shengping Zhang, Chuangui Wang, Wen Zhang,

Electrochemical Analysis and Applications

Abstract α‐Synuclein (α‐SYN) is a very important neuronal protein that is associated with Parkinson’s disease. In this paper, we utilized Au‐doped TiO 2 nanotube arrays to design a photoelectrochemical immunosensor for the detection of α‐SYN. The highly ordered TiO 2 nanotubes were fabricated by using an electrochemical anodization technique on pure Ti foil. After that, a photoelectrochemical deposition method was exploited to modify the resulting nanotubes with Au nanoparticles, which have been demonstrated to facilitate the improvement of photocurrent responses. Moreover, the Au‐doped TiO 2 nanotubes formed effective antibody immobilization arrays and immobilized primary antibodies (Ab 1 ) with high stability and bioactivity to bind target α‐SYN. The enhanced sensitivity was obtained by using {Ab 2 ‐Au‐GOx} bioconjugates, which featured secondary antibody (Ab 2 ) and glucose oxidase (GOx) labels linked to Au nanoparticles for signal amplification. The GOx enzyme immobilized on the prepared immunosensor could catalyze glucose in the detection solution to produce H 2 O 2 , which acted as a sacrificial electron donor to scavenge the photogenerated holes in the valence band of TiO 2 nanotubes upon irradiation of the other side of the Ti foil and led to a prompt photocurrent. The photocurrents were proportional to the α‐SYN concentrations, and the linear range of the developed immunosensor was from 50 pg mL −1 to 100 ng mL −1 with a detection limit of 34 pg mL −1 . The proposed method showed high sensitivity, stability, reproducibility, and could become a promising technique for protein detection.