Sensitive electrochemical detection of amyloid beta peptide in human serum using an interdigitated chain-shaped electrode

In this study, we developed a small size, low cost, highly sensitive electrochemical biosensor with a low limit of detection by immobilizing specific anti-amyloid-β (aβ) antibody onto a self-assembled monolayer functionalized interdigitated chain-shaped electrode (anti-aβ/EDC–NHS/SAM/ICE). The anti-aβ/EDC–NHS/SAM/ICE specifically detects aβ 1–42 peptide (a peptide 1–42 amino acids long), which is one of main biomarkers of Alzheimer's disease in human serum (HS). Electrochemical impedance spectroscopy (EIS) was used to characterize the impedance change of the anti-aβ/EDC–NHS/SAM/ICE biosensor for aβ 1–42 detection, which provided a wide linear range of detection from 10−3–103 ng mL−1, and a low limit of detection of aβ in HS (100 pg mL−1) much lower than the limit of detection of CSF aβ 1–42 (∼500 pg mL−1), and other biosensors. Therefore, the developed biosensor is sensitive enough to be used for the diagnosis of early stage Alzheimer's disease. •The specific anti-aβ antibody functionalized ICE electrode is designed to improve electric field homogeneity.•Label-free and real-time detection of aβ 1–42 using electrochemical impedance spectroscopy.•A low LOD (100 pg mL−1) with a linear detection range of 10−3–103 ng mL−1 in human serum is reported.