Synergistic effect of Co-MoS₂ and Au-rGO nanomaterials: Layer-by-layer electrochemical immunosensor realizes high...

Quantitative detection of amyloid-beta oligomers (AβO) is crucial for early diagnosis of Alzheimer's disease (AD). Herein, a simple, label-free electrochemical immunosensor was constructed by integrating cobalt-doped molybdenum disulfide (Co-MoS₂) and gold-doped reduced graphene oxide (Au-rGO) via hydrothermal and self-assembly methods. The Co-MoS₂/Au-rGO/GCE composite electrode was then immobilized with anti-Aβ42 antibodies. Differential pulse voltammetry (DPV) showed a linear detection range of 1.1 × 10^-9 M to 1.1 × 10^-14 M for AβO, with a limit of detection (LOD) of 6.87 × 10^-15 M (S/N = 3). Quality control serum tests confirmed excellent reproducibility, stability, and accuracy. This immunosensor enables sensitive AβO determination and holds potential for point-of-care testing (POCT) of other AD biomarkers.