DNA Framework-Mediated Electrochemical Biosensing Platform for Amplification-Free MicroRNA Analysis

Area of Science:

• Biomolecular Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• MicroRNAs (miRNAs) are crucial biomarkers for early disease diagnosis, particularly in cancers.
• Detecting low-level miRNAs in complex biological samples remains a significant analytical challenge.
• Existing methods often require cumbersome procedures or nucleic acid amplification.

Purpose of the Study:

• To develop a facile and highly sensitive biosensing strategy for microRNA detection.
• To establish a modular framework nucleic acid (FNA) platform for homogeneous and heterogeneous biosensing.
• To enable early cancer diagnosis through sensitive miRNA detection in clinical samples.

Main Methods:

• A two-phase biosensing strategy combining homogeneous and heterogeneous reactions on a modular FNA platform.
• Phase 1: Homogeneous binding of target miRNAs by free DNA probes in solution.
• Phase 2: Selective transfer of DNA-RNA complexes to an FNA-functionalized electrode for electrochemical signal transduction.

Main Results:

• Detection of microRNA-141 (a cancer marker) down to 1 aM without nucleic acid amplification.
• Achieved a broad dynamic detection range spanning 10 orders of magnitude.
• Demonstrated multiplex miRNA detection, discrimination of single-base mismatches, and detection in 50 ng of total RNA from cancer cells.

Conclusions:

• The developed FNA platform offers a sensitive, facile, and efficient approach for miRNA detection.
• This biosensing strategy holds promise for the high-throughput screening of early cancer biomarkers.
• The system successfully discriminated between prostate cancer cells and normal cells, highlighting its clinical diagnostic potential.