Sensitive MicroRNA detection via single nanoparticle collision electrochemistry using DNA-functionalized silver...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Molecular Diagnostics

Background:

• MicroRNA (miRNA) quantification is crucial for disease diagnostics and understanding molecular mechanisms.
• Existing miRNA detection methods often lack sensitivity or involve complex procedures.

Purpose of the Study:

• To develop a novel, highly sensitive electrochemical sensor for detecting miRNA-21.
• To utilize silver nanoparticle (AgNP) collision-oxidation and DSN-mediated signal amplification for enhanced detection.

Main Methods:

• Functionalized AgNPs with ssDNA probes to block electrode contact in an "off" state.
• Utilized DSN enzyme to cleave miRNA-duplexes upon hybridization, exposing AgNPs.
• Detected miRNA-21 via oxidation-induced current transients in an "on" state, correlating signal frequency with concentration.

Main Results:

• Achieved a low limit of detection (LOD) of 0.011 fM for miRNA-21.
• Established a linear detection range from 0.05 fM to 1000 fM.
• Demonstrated high specificity, distinguishing target miRNA from analogs, and successful detection in spiked human serum (96.7-112% recovery).

Conclusions:

• The developed electrochemical sensor offers a simple, sensitive, and specific method for miRNA-21 quantification.
• The sensor shows significant potential for clinical applications, particularly in liquid biopsy for disease diagnostics.
• This approach provides a powerful tool for analyzing low-abundance miRNAs in complex biological matrices.