An innovative electrochemiluminescent immunosensor using dual amplified signals from AuNPs@CoSn(OH)6 for the detection of AD-biomarker: amyloid-beta 1-40

Abstract

Alzheimer’s disease (AD) is a degenerative condition of the nervous system that causes severe damage to patients’ daily activities as well as the quality of their life. Amyloid beta 1-40 protein (Aβ40), which is involved in the formation of cerebral plaques, is one of the crucial biomarkers related to AD. Herein, a novel and highly sensitive immunosensor for the detection of Aβ40 is developed. Using a reinforced indium tin oxide coated glass by the nanocomposite of gold nanoparticle enhanced CoSn(OH)6 (AuNPs@CoSn(OH)6) to trigger the electrochemiluminescence (ECL) of luminol as the sensing signal, the immunosensor is fabricated by immobilizing the Aβ40 antibody onto it. By integrating the high immune specificity, the excellent conductivity and catalytic activity of nanocomposite, the resultant immunosensor can be successfully employed to detect the target in real samples. The formation of the immune complex leads to increased steric hindrance and electron transfer resistance, which in turn causes a declined ECL output when the target Aβ40 binds to antibody on the sensor surface. Under optimized conditions, the developed ECL immunosensor exhibits a linear response for Aβ40 ranging from 1 to 800 pg/mL and a low detection limit of 0.47 pg/mL. Experimentally, it is demonstrated to be highly sensitive, specific, reproducible and stable. This work extends the application of perovskite CoSn(OH)6 and AuNPs in the field of ECL immunosensing and provides a novel strategy for clinical research on Alzheimer’s disease.