Ultrasensitive electrochemical immunosensor for HE4 based on rolling circle amplification.

Area of Science:

• Electrochemistry
• Nanomaterials Science
• Biomedical Engineering

Background:

• Human epididymis-specific protein 4 (HE4) is a significant biomarker for ovarian cancer.
• Sensitive and accurate detection methods for HE4 are crucial for early diagnosis and monitoring.
• Existing detection techniques may have limitations in sensitivity, cost, or complexity.

Purpose of the Study:

• To develop a novel electrochemical immunoassay system for sensitive and accurate detection of HE4.
• To utilize a chitosan-titanium carbide nanocomposition film for enhanced electrode performance.
• To integrate rolling circle amplification (RCA) for signal amplification.

Main Methods:

• Fabrication of a chitosan-titanium carbide (TiC) nanocomposition film on an ITO electrode.
• Electrodeposition of gold (Au) nanoparticles and adsorption of anti-HE4 capture antibodies.
• Sandwich immunoreaction with HE4, followed by biotin-streptavidin immobilization of primer DNA.
• Rolling circle amplification (RCA) and detection using doxorubicin hydrochloride intercalation monitored by differential pulse voltammetry (DPV).

Main Results:

• The developed electrochemical immunoassay demonstrated a linear response to HE4 in the range of 3-300 pM.
• A low detection limit of 0.06 pM was achieved for HE4.
• Surface characterization using SEM, AFM, and EIS confirmed the successful fabrication and layered structure.
• The system showed good accuracy and renewable ability in HE4 detection.

Conclusions:

• The novel electrochemical immunoassay system provides a highly sensitive and accurate method for HE4 detection.
• The combination of chitosan-TiC nanocomposition, Au nanoparticles, and RCA offers significant signal amplification.
• This platform holds promise for clinical applications in early ovarian cancer diagnosis and monitoring.