A novel NH2-UiO-66/TAPA-DHNDA-COF heterojunction photocathode paired with NiCo2S4@ZnIn2S4 photoanode for self-powered photoelectrochemical detection of Aβ42 and Aβ40 based on redox cycling signal amplification.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder, and early detection of amyloid-beta peptides Aβ42 and Aβ40 is critical for timely intervention. Herein, a novel self-powered photoelectrochemical (SP-PEC) platform was developed for the detection of Aβ42 and Aβ40, using NH2-UiO-66/TAPA-DHNDA-COF (NU66/T-D-COF) as the photocathode and NiCo2S4@ZnIn2S4 (NCS@ZIS) as the photoanode. The NU66/T-D-COF heterojunction was synthesized via Schiff-base reaction to deliver strong cathodic photocurrent and efficient charge separation. CdTe quantum dots (CdTe-QDs) and CdS quantum dots (CdS-QDs) were used as signal probes for Aβ42 and Aβ40, respectively. Under optimal conditions, the SP-PEC platform exhibited a wide linear range from 1 fg/mL to 100 ng/mL, with detection limits of 0.24 fg/mL for Aβ42 and 0.33 fg/mL for Aβ40. The platform showed excellent stability, selectivity, and satisfactory recovery in real biological samples, providing a promising tool for early and sensitive AD biomarker diagnosis.