Electrochemical Detection of Alzheimer’s Disease Biomarker, β-Secretase Enzyme (BACE1), With One-Step Synthesized Reduced Graphene Oxide

Abstract

β-Secretase1 (BACE1) catalyzes the rate-limiting step in the generation of amyloid-β peptides, that is, the principal component involved in the pathology of Alzheimer’s disease (AD). Recent research studies show correlation between blood and cerebrospinal fluid (CSF) levels of BACE1 with the pathophysiology of AD. In this study, we report one-step synthesized reduced graphene oxide (rGO), activated via carbodiimide chemistry, conjugated with BACE1 antibody (Ab), and immobilized on fluorine-doped tin oxide (FTO) electrodes for rapid detection of BACE1 antigen (Ag) for AD diagnosis. The synthesis and fabrication steps were characterized using different types of spectroscopic, X-ray analytic, microscopic, and voltametric techniques. Various parameters including nanomaterial/Ab concentration, response time, pH, temperature, and rate of scan were standardized for maximum current output using the modified electrode. Final validation was performed via detection of BACE1 Ag ranging from 1 fM to 1 µM, with a detection limit of 0.64 fM in buffer samples and 1 fM in spiked serum samples, as well as negligible cross-reactivity with neurofilament Ag in buffer, spiked serum, and spiked artificial CSF. The proposed immunosensor gave a quick result in 30 s, and good repeatability and storage stability for a month, making it a promising candidate for sensitive, specific, and early diagnosis of AD. Thus, the fabricated electrochemical biosensor for BACE-1 detection improves detection performance compared to existing sensors as well as reduces detection time and cost, signifying its potential in early diagnosis of AD in clinical samples.

Alzheimer's Disease Diagnosis in the Preclinical Stage: Normal Aging or Dementia

“…These biological interactions can change the sensing interface properties (i.e., capacitance or conductance) of the p-type or ntype transistor. Consequently, in organic transistor biosensors, taking advantage of nanostructures, such as ZnO, MoS2 nanopores, carbon nanotubes, nanowires, copolymers, and graphene sheets (or nanoribbons) on the gate or channel makes them highly sensitive devices for biosensing [83,84]. In addition to enhancing the sensing surface by nanomaterials, a concave surface like crumpled graphene showed higher sensitivity than a flat one [84].…”

“…While transistor-based biosensors commonly offer low power consumption, appropriate sensitivity, and flexibility, the fabrication and biofunctionalization of electrochemical transistors tend to be more complicated than electrode ones. This complexity can also include the necessity for high-precision readout circuits to achieve a high signal-to-noise ratio [83].…”

“…Due to the importance of photoactive nanomaterials in converting light energy to photoelectrical signals and their role in analytical performance, various kinds of active transducers have been introduced. These materials can be categorized as semiconductors (i.e., ITO, TiO2, quantum dots) and the combination of semiconductors with other semiconducting structures or carbon-based nanomaterials [82,83]. PEC biosensors are intriguing because of their advantages, such as fast response, cost-effectiveness, and proper selectivity.…”

Immuno-chromatic probe based lateral flow assay for point-of-care detection of Japanese encephalitis virus NS1 protein biomarker in clinical samples using a smartphone-based approach

“…12,13 While there have been reports of highly sensitive sensors [14][15][16][17] developed for JEV antigen (Ag) detection, most of them are electrochemical-based and expensive as well as difficult to fabricate, require skilled handling, and most importantly, are not portable point-of-care (PoC) devices. [18][19][20][21][22][23][24] To overcome these limitations of existing sensors, Ag targeting immunochromatographic lateral ow assays (LFAs) are being developed for rapid bedside detection of various infectious diseases. 25,26 LFAs comprise prefabricated strips of a carrier probe containing dry reagents that are activated by addition of a uid sample, 27 and the absence/presence of the target analyte is indicated by the appearance of coloured lines on the membrane.…”

A brief review on novel biomarkers identified and advanced biosensing technologies developed for rapid diagnosis of Japanese Encephalitis Virus

“…These are used as the immobilized biorecognition element (Roberts et al 2021b , 2022b ) on the fabricated sensor such as antibody (Holford et al 2012 ), aptamer (Song et al 2008 ), peptide (Liu et al 2015 ), enzyme (Kim et al 2011 ), etc. Different nanomaterial (Mishra et al 2019 ) for example graphene (Shahdeo et al 2020 ; Dey et al 2022 ; Mahari et al 2022 ), graphitic carbon nitride (Chouhan et al 2021 ), gold (Shahdeo et al 2022 ) etc. may be incorporated as signal enhancers in the biosensing system.…”