Dual on-the-move electrochemical immunoassays for the simultaneous determination of amyloid-β (1−42) and Tau in Alzheimer's patient samples

Abstract

Here, we report catalytic micromotors (MM)-based electrochemical immunoassays for the on-the-move dual and simultaneous determination of Amyloid-β (Aβ-42) and Tau protein (Tau) (MM Aβ-42 -MM Tau ) as relevant Alzheimer’s disease biomarkers in brain tissue, cerebrospinal fluid, and plasma diagnosed samples. Combining the binding capacity of the antibody's functionalized polypyrrole (PPy) layer of MM with the self-propulsion from the PtNPs layer thanks to the decomposition of hydrogen peroxide, the approach yielded excellent detection limits (LOD Aβ-42 =0.04 ng/mL, LOD Tau = 0.4 pg/mL) using low sample volumes (30 µL) and short analysis times (15 min) to detect both biomarkers. Quantitative analysis by MM Aβ-42 -MM Tau was carried out without any clinical sample dilution (linear ranges are between 0.1 and 5 ng/mL for Aβ-42 and from 1 to 10 6 pg/mL in the case of Tau), highlighting the versatility of the approach to quantify Aβ-42 and Tau levels at different dynamic ranges. MM Aβ-42 -MM Tau showed superior analytical capabilities to the single molecule counting technology (SMCx) during quantitative analysis in all sample classes tested, reporting a difference in quantitative levels for both biomarkers between healthy and diseased individuals and an increase in the levels with disease progression, except in plasma samples where no relationship between biomarker levels and disease progression was found. • Dual micromotor immunoassays for Alzheimer’s disease diagnosis • On-the-move dual immunoassays for simultaneous Aβ-42 and tau determination • Micromotor-based biomarkers analysis in brain, cerebrospinal fluid, and plasma • Micromotors as creative nano architectonics for Alzheimer’s disease diagnosis • Micromotors are tailored and promising tools for Alzheimer’s disease diagnosis

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