A label-free biosensor based on graphene and reduced graphene oxide dual-layer for electrochemical determination of beta-amyloid biomarkers

Abstract

A label-free biosensor is developed for the determination of plasma-based Aβ 1-42 biomarker in Alzheimer's disease (AD). The platform is based on highly conductive dual-layer of graphene and electrochemically reduced graphene oxide (rGO). The modification of dual-layer with 1-pyrenebutyric acid N-hydroxysuccinimide ester (Pyr-NHS) is achieved to facilitate immobilization of H31L21 antibody. The effect of these modifications were studied with morphological, spectral and electrochemical techniques. The response of the biosensor was evaluated using differential pulse voltammetry (DPV). The data was acquired at a working potential of~180 mV and a scan rate of 50 mV s −1. A low limit of detection (LOD) of 2.398 pM is achieved over a wide linear range from 11 pM to 55 nM. The biosensor exhibits excellent specificity over Aβ 1-40 and ApoE ε4 interfering species. Thus, it provides a viable tool for electrochemical determination of Aβ 1-42. Spiked human and mice plasmas were used for the successful validation of the sensing platform in bio-fluidic samples. The results obtained from mice plasma analysis concurred with the immunohistochemistry (IHC) and magnetic resonance imaging (MRI) data obtained from brain analysis.

Graphene‐Based Nanotechnology in Neurodegenerative Disorders

“…[ 21 ] The combination of noncovalent and covalent binding using bifunctional linkers has also been reported. [ 46 ]…”

Assessing Surface Coverage of Aminophenyl Bonding Sites on Diazotised Glassy Carbon Electrodes for Optimised Electrochemical Biosensor Performance

“…In order to confirm this behaviour in a practical sensor, we used diazonium functionalisation to prepare a sensor, incorporating a carboxyl-terminated anti-beta amyloid antibody specific to Aβ (1-42) peptide, a potential marker for Alzheimer's disease. In this case, the sensor response is a reduction in current in differential pulse voltammetry (DPV) as the bound peptide acts as a barrier to electron transfer at the electrode surface [46,47]. Figure 4 shows the percentage current reduction (%I R ) plotted against the log of analyte concentrations.…”

Structure, Properties, and Electrochemical Sensing Applications of Graphene‐Based Materials

“…Altered levels of the beta-amyloid peptide biomarker (Aβ 1-42 ), which consists of 42 amino acids, in biological fluids, can be used to diagnose Alzheimer's disease, one of the most studied chronic diseases nowadays. Sethi et al [181] developed a biosensor composed of graphene, rGO, the N-hydroxysuccinimide ester of 1-pyrenobutyric acid (Pyr-NHS), and the H 31 L 21 antibody for the specific quantification of Aβ 1-42 in human plasma. The sensor presented a good response in the Aβ 1-42 concentration range of 11 pmol L À 1 -55 nmol L À 1 and an LOD of 2.4 pmol L À 1 , and provided a simpler and less expensive testing procedure than similar tests for Aβ .…”