Development of a sensitive electrochemical immunosensor using polyaniline functionalized graphene quantum dots for...

Area of Science:

• Electrochemistry
• Biomaterials Science
• Clinical Diagnostics

Background:

• Depression diagnosis relies on subjective assessments and lacks objective molecular markers.
• Heat shock protein 70 (HSP70) has emerged as a potential biomarker for depression.
• Novel electrochemical methods are needed for sensitive and early detection of depression biomarkers.

Purpose of the Study:

• To develop a novel electrochemical immunosensor for the early screening of depression.
• To utilize polyaniline functionalized graphene quantum dots (PAGD) as a platform for detecting heat shock protein 70 (HSP70).
• To establish a reliable and objective method for molecular-level depression diagnosis.

Main Methods:

• In-situ polymerization to prepare polyaniline functionalized graphene quantum dots (PAGD).
• Construction of an electrochemical immunosensor by immobilizing HSP70 onto PAGD modified glassy carbon electrode (HSP70/PAGD/GCE).
• Electrochemical characterization using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).
• Competitive immunoassay utilizing horseradish peroxidase labeled antibody.

Main Results:

• The fabricated immunosensor (HRP-Strept-Biotin-Ab-HSP70/PAGD/GCE) demonstrated a negative correlation between detection signal and HSP70 concentration.
• Achieved a wide linear range of 0.0976-100 ng/mL for HSP70 detection.
• Obtained a low detection limit of 0.05 ng/mL (at 3σ).
• Successfully applied the immunosensor to detect HSP70 in human plasma samples with good precision, stability, and reproducibility.

Conclusions:

• The study presents a novel and convenient electrochemical immunosensor for early clinical screening of depression markers.
• The PAGD-based immunosensor provides a reliable and objective method for molecular-level depression diagnosis.
• This approach holds promise for improving the early detection and management of depression.