Sensitive dual-mode sensing platform for Amyloid β detection: Combining dual Z-scheme heterojunction enhanced photoelectrochemistry analysis and dual-wavelength ratiometric electrochemiluminescence strategy

Key Words:ALZHEIMERS-DISEASE; OLIGOMERS; PROTEIN; CHEMILUMINESCENCE; FIBRILS

Abstract:As a tumor biomarker, the accumulation of amyloid beta oligomers (A beta o) in the brain has been suggested as a key feature in the pathogenesis and progression of Alzheimer's disease (AD). In this work, we designed a novel photoelectrochemical (PEC) and electrochemiluminescence resonance energy transfer (ECL-RET) dual-mode biosensor to achieve ultra-sensitive detection of A beta o. Specifically, the electrode surface modified Carbon Dots (C Dots) and the electrodeposited polyaniline (PANI) film formed a Z-scheme heterojunction reversing the photocurrent signal, and then the A beta o specific recognition peptide was attached to the surface via amide bonding between the amino group of PANI and carbonyl group of peptide. After that, in the presence of CdTe labeled specific recognition aptamer for A beta (CdTe-Apt), A beta o was captured to construct a sandwich-type biosensor and exhibited a significantly enhanced cathodic photocurrent response because the formed dual Z-scheme hetero-junction promoted charge separation efficiency. Interestingly, the proposed biosensor also caused a ratiometric change in the ECL intensity at 555 nm and 640 nm. Therefore, the developed biosensor achieved dual-mode detection of A beta o, where the PEC detection range of A beta o was from 10 fM to 0.1 mu M (with a detection limit of 4.27 fM) and the ECL method provided a linear detection range of 10 fM to 10 nM (with a detection limit of 6.41 fM). The stability and reliability of the experimental results indicate that this has been a promising biosensing pattern and could be extended to the analysis of other biomarkers.

Volume:237

Issue:

Translation or Not:no