Double-site DNA walker based ternary electrochemiluminescent biosensor

Area of Science:

• Electrochemistry
• Biomolecular Engineering
• Nanotechnology

Background:

• Carcinoembryonic antigen (CEA) is a significant biomarker for various cancers.
• Sensitive and accurate detection of CEA is crucial for early disease diagnosis and monitoring.
• Existing biosensing methods often face challenges in sensitivity and specificity.

Purpose of the Study:

• To develop a novel electrochemiluminescence (ECL) biosensor for sensitive CEA detection.
• To utilize a Ru(dcbpy)(bpy)22+/tripropylamine (TPrA)/TiO2 nanocrystallines (TiO2 NCs) ternary system as the ECL core.
• To implement an enzyme-driven double-site DNA walker strategy for signal amplification.

Main Methods:

• Fabrication of an ECL biosensor using Ru(dcbpy)(bpy)22+/TPrA/TiO2 NCs.
• Employing anatase TiO2 NCs as a coreaction accelerator to enhance ECL signals.
• Utilizing a CEA-triggered protein-aptamer cycle amplification to generate double-site DNA walkers.
• Implementing a "signal-off" mechanism where DNA walkers detach the ECL emitter.

Main Results:

• The biosensor demonstrated a "signal-on" state facilitated by TiO2 NCs accelerating TPrA oxidation.
• The "signal-off" state was achieved through DNA walkers triggering the detachment of the Ru complex.
• Achieved a wide linear range from 500 pg/mL to 50 fg/mL for CEA detection.
• Obtained a low detection limit of 10.5 fg/mL for CEA.

Conclusions:

• The developed ECL biosensor offers high sensitivity and a broad detection range for CEA.
• The strategy effectively combines an ECL ternary system with DNA walker amplification.
• This approach provides a promising platform for sensitive biomolecule detection and disease diagnosis.