Cascade signal amplification-based fluorescent biosensor utilizing exonuclease III and self-locking DNAzyme synergy...

Area of Science:

• Biochemistry
• Molecular Biology
• Nanotechnology

Background:

• MicroRNAs (miRNAs) are key gene regulators implicated in diseases like cancer.
• Current miRNA detection methods suffer from low sensitivity and interference in biological samples, limiting clinical use.
• Accurate miRNA detection is crucial for early disease diagnosis and liquid biopsy.

Purpose of the Study:

• To develop a highly sensitive and specific fluorescence biosensor for microRNA detection.
• To overcome the limitations of existing miRNA detection techniques.
• To enable reliable miRNA profiling for early cancer detection and liquid biopsy.

Main Methods:

• A cascade-amplified fluorescence biosensor integrating exonuclease III (Exo III) and self-locking DNAzyme (SLD).
• Exo III-mediated cyclic digestion of target-induced heteroduplexes for signal amplification.
• Conformation-gated DNAzyme catalysis for specific target recognition and secondary amplification.

Main Results:

• Achieved label-free, isothermal detection of miRNA-155 with a wide linear range (50 fM-10 pM).
• Demonstrated a low limit of detection (LOD) of 4.96 fM for miRNA-155.
• Exhibited robust specificity and minimal interference in complex serum matrices, overcoming homologous miRNA cross-reactivity.

Conclusions:

• The developed biosensor offers a cost-effective, high-precision platform for miRNA profiling.
• The synergistic integration of Exo III and SLD provides dual amplification for enhanced sensitivity.
• This technology holds significant promise for point-of-care diagnostics and liquid biopsy-based early cancer detection.