Electrochemical Immunosensor Using COOH-Functionalized 3D Graphene Electrodes for Sensitive Detection of Tau-441...

Area of Science:

• Biomedical Engineering
• Materials Science
• Neuroscience

Background:

• Early Alzheimer's disease (AD) diagnosis is critical for treatment but current methods are complex and costly.
• Graphene biosensors offer a promising, affordable alternative for point-of-care diagnostics.
• Oxidation of graphene's lattice can reduce conductivity, hindering biomolecule immobilization for biosensor development.

Purpose of the Study:

• To develop a cost-effective electrochemical immunosensor for early Alzheimer's disease diagnosis.
• To preserve graphene conductivity while enabling efficient functionalization for biomarker detection.
• To create a sensitive and selective platform for detecting AD biomarkers in biological samples.

Main Methods:

• Fabrication of an electrochemical immunosensor using carboxyl-modified graphene foam (COOH-GF) electrodes.
• Utilizing π-π non-covalent interactions for COOH modification and EDC-NHS chemistry for antibody immobilization.
• Detection of tau-441 biomarker using differential pulse voltammetry (DPV) in phosphate-buffered saline (PBS) and human serum.

Main Results:

• The immunosensor achieved a wide detection range of 1 fM-1 nM for tau-441.
• A highly sensitive limit of detection (LOD) of 0.14 fM was obtained in both PBS and human serum.
• Demonstrated excellent selectivity against other AD-related proteins (tau-217, tau-181, Aβ peptides) and BSA.

Conclusions:

• The developed COOH-GF electrochemical immunosensor is a highly sensitive and selective tool for early Alzheimer's disease detection.
• This cost-effective biosensor preserves graphene conductivity, overcoming a key challenge in graphene-based sensor development.
• The findings support its potential for point-of-care diagnostics, facilitating timely intervention for Alzheimer's disease.