Electrochemiluminescence Biosensor Based on a Self-protected DNAzyme Walker with a Circular Bulging DNA Shield for...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Molecular Biology

Background:

• MicroRNA (miRNA) detection is vital for early disease diagnosis.
• Existing biosensors often lack sensitivity and efficiency for low-abundance biomarkers.
• Novel strategies are needed for ultrasensitive and rapid miRNA detection.

Purpose of the Study:

• To develop an ultrasensitive electrochemiluminescence (ECL) biosensor for microRNA (miRNA) detection.
• To integrate a self-protected DNAzyme walker for enhanced catalytic activity and signal amplification.
• To demonstrate the potential for early cancer diagnosis using this novel biosensor.

Main Methods:

• Fabrication of a gold nanoparticle-modified electrode.
• Integration of a self-protected DNAzyme walker with a target-binding domain.
• Utilizing target-induced activation of the DNAzyme walker for substrate cleavage.
• Monitoring ECL signal changes upon Ru-labeled DNA fragment liberation.

Main Results:

• The self-protected DNAzyme walker demonstrated high catalytic cleavage activity upon target miRNA binding.
• The biosensor achieved an ultrasensitive limit of detection for Let-7a miRNA at 51.4 aM.
• A wide linear range of detection from 100 aM to 100 pM was established.
• ECL signal was significantly reduced due to the liberation of Ru-labeled DNA fragments.

Conclusions:

• The developed ECL biosensor offers a promising platform for ultrasensitive miRNA detection.
• The self-protected DNAzyme walker strategy enhances detection sensitivity and efficiency.
• This approach holds significant potential for early cancer diagnosis and biomarker research.