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A photoelectrochemical sensor for highly sensitive detection of amyloid beta based on sensitization of Mn:CdSe to Bi2WO6/CdS

Xu, Rui, Wei, Dong, Du, Bin, Cao, Wei, Fan, Dawei, Zhang, Yong, wei, Qin, Ju, Huangxian
Biosensors & bioelectronics 2018 v.122 pp. 37-42
Alzheimer disease, amyloid, antibodies, detection limit, electrodes, energy, immunosensors, manganese, nanoparticles, neurotoxicity
A high sensitivity photoelectrochemical (PEC) immunosensor for amyloid beta (Aβ) detection, which has great neurotoxic effect on the progression of Alzheimer's disease (AD), was presented based on the sensitization of Mn²⁺ doped CdSe (Mn:CdSe) to Bi2WO6/CdS electrode. Bi2WO6 was synthesized successfully with a unique flower-like amorphous structure, providing a merit to load functional CdS for obtaining an expected PEC response. Mn:CdSe was used to label Aβ for acquiring Mn:CdSe-Aβ bioconjugate and enhancing the detection sensitivity via the competitive immunoreaction of Mn:CdSe-Aβ and Aβ with antibody immobilized on Bi2WO6/CdS electrode. The doped of Mn²⁺ in CdSe nanoparticles could induce energy defect that impeded the recombination of photo-generated charges, and greatly enhanced PEC response for ultrasensitive detection of Aβ. The proposed immunosensor for Aβ showed a linear range of 0.2 pg mL⁻¹–50 ng mL⁻¹ with a detection limit of 0.068 pg mL⁻¹, also with good stability, high selectivity, and acceptable reproducibility. The sensitization of Mn:CdSe provided a new way for preparation of highly sensitive protein biosensors.