Electrochemical impedance immunosensor based on three-dimensionally ordered macroporous gold film

Area of Science:

• Electrochemistry
• Biosensor Technology
• Nanomaterials

Background:

• C-reactive protein (CRP) is a key biomarker for inflammation and cardiovascular disease.
• Accurate and sensitive detection of CRP is crucial for early diagnosis and disease management.
• Existing CRP detection methods can be complex, time-consuming, or require labeling.

Purpose of the Study:

• To develop a novel, label-free immunosensor for sensitive C-reactive protein (CRP) detection.
• To utilize a three-dimensional ordered macroporous (3DOM) gold film for enhanced sensor performance.
• To validate the immunosensor's accuracy using clinical serum samples.

Main Methods:

• Fabrication of a 3DOM gold film electrode using an inverted opal template.
• Modification of the 3DOM gold electrode with CRP antibodies via 3-mercaptopropionic acid (MPA) for covalent conjugation.
• Detection of CRP using electrochemical impedance spectroscopy (EIS) to measure changes in electron-transfer resistance (R(et)).
• Characterization of the electrode surface area using cyclic voltammetry (CV).

Main Results:

• The 3DOM gold film electrode exhibited a surface area 14.4 times larger than a bare flat electrode.
• The 3DOM gold film provided enhanced conductivity, stability, and a biocompatible microenvironment.
• The developed immunosensor demonstrated a linear relationship between R(et) and the logarithm of CRP concentration (0.1–20 ng mL⁻¹).
• The immunosensor showed acceptable accuracy when detecting CRP levels in human serum samples.

Conclusions:

• A highly sensitive and label-free electrochemical immunosensor for CRP detection was successfully developed.
• The 3DOM gold film electrode significantly enhances sensor performance due to its increased surface area and improved properties.
• This novel immunosensor shows potential for accurate and efficient clinical diagnostics of CRP levels.