Integrating Acridinium Ester with a Soluble Macromolecular Amplification Carrier for Ultrasensitive Detection of Aβ1-42 in Plasma

. The assay exhibited excellent specificity, with negligible cross-reactivity (<0.5%) to other amyloid isoforms, high precision indicated by coefficients of variation below 8%, and robust reagent stability under both accelerated and onboard conditions. Analysis of clinical samples demonstrated strong correlation (Spearman's ρ = 0.983) and minimal bias compared to a commercial reference method, confirming the assay's reliability. Collectively, this study successfully expanded the application of the Ficoll400-SA signal amplification carrier from enzymatic chemiluminescence assays to the AE direct chemiluminescence platform. Moreover, these findings validate the Ficoll400-SA platform as a versatile, highly sensitive, and automatable approach for detecting low-abundance biomarkers, with significant potential to advance the early diagnosis of Alzheimer's disease and biomarker research.