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

A high sensitivity photoelectrochemical (PEC) immunosensor for amyloid beta (A beta) 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 A beta for acquiring Mn:CdSe-A beta bioconjugate and enhancing the detection sensitivity via the competitive immunoreaction of Mn:CdSe-A beta and A beta 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 A beta. The proposed immunosensor for A beta 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.