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.