Self-sacrificial label assisted electroactivity conversion of sensing interface for ultrasensitive electrochemical...

Area of Science:

• Electrochemistry
• Biosensors
• Nanotechnology

Background:

• Electrochemical immunoassays face limitations like signal leaking and reduced catalytic activity.
• Existing strategies struggle with probe hindrance and signal degradation.
• Need for sensitive and stable detection methods is critical.

Purpose of the Study:

• To develop a novel sensitivity amplification strategy for electrochemical immunoassays.
• To overcome limitations of signal leaking, catalytic degradation, and probe hindrance.
• To achieve ultrasensitive detection of carbohydrate antigen 125 (CA 125).

Main Methods:

• Utilized Fe3+-loaded polydopamine (Fe3+-PDA) nanoparticles as self-sacrificial labels.
• Developed a sensing interface that converts from electrochemically inactive to active.
• Employed Prussian blue (PB) precursor solution for electroactive PB nanoparticle growth.
• Leveraged Fe3+ release to trigger PB NP formation and enhance catalysis.

Main Results:

• Achieved ultrasensitive quantification of CA 125 with a wide detection range (0.00001–1000 U mL−1).
• Demonstrated a low detection limit of 0.25 × 10−6 U mL−1.
• The strategy effectively amplified redox signals via PB NP catalysis of H2O2.
• Minimized signal leaking and catalytic activity degradation.

Conclusions:

• The self-sacrificial label-assisted strategy offers a robust method for electrochemical immunoassay sensitivity.
• This approach successfully converts inactive interfaces to highly electroactive ones.
• The developed method provides a promising platform for sensitive biomarker detection.