Sensitive detection of amyloid-β42 using a graphitic carbon nitride-boosted electrochemical peptide biosensor.

Abstract

Amyloid-beta 42 (Aβ42) is a key biomarker associated with Alzheimer's disease (AD), and its plasma levels serve as a crucial indicator for early detection of AD. In this study, an electrochemical impedimetric biosensor capable of rapid, sensitive, and specific quantitative determination of Aβ42 protein was designed for the early diagnosis of Alzheimer's disease. The composite two-dimensional nanomaterial reduced graphene oxide/protonated graphitic carbon nitride (p-CN/rGO) was used for signal amplification, with gold nanoparticles (AuNPs) providing molecular binding sites. An artificially designed peptide (sequence: CPPPEKEKEKKLVFF) enables specific recognition of Aβ42, and the fabrication and quantitative determination of Aβ42 were monitored by electrochemical impedance spectroscopy (EIS). The fabricated electrochemical biosensing platform exhibits a broad linear detection range (1 fg/mL to 1 ng/mL) and a low limit of detection (1.97 × 10- 2 fg/mL), enabling sensitive and precise detection of Aβ42 protein. Furthermore, the biosensor was investigated for excellent reproducibility, stability, selectivity, and regeneration, and demonstrates reliability in the practical analysis of Aβ42 in simulated human serum. Thus, this electrochemical biosensing platform offers a novel approach to blood-based detection of Aβ, providing an experimental foundation for early diagnosis and research into the pathological mechanisms of AD.

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