Highly sensitive miRNA-21 detection with enzyme-free cascade amplification biosensor.

Area of Science:

• Biomedical Engineering
• Molecular Diagnostics
• Biochemistry

Background:

• MicroRNA-21 is a key biomarker in clinical diagnosis.
• Sensitive and specific detection of microRNAs is crucial for early disease identification.
• Existing detection methods often require complex procedures or enzymes.

Purpose of the Study:

• To develop a highly sensitive, enzyme-free fluorescence biosensor for microRNA-21 detection.
• To combine catalytic hairpin assembly (CHA) and entropy-driven amplification for enhanced signal.
• To validate the biosensor's performance in biological samples like human serum and cell lysates.

Main Methods:

• Utilized a cascade amplification strategy integrating CHA and entropy-driven amplification.
• MicroRNA-21 initiates CHA, releasing a trigger for subsequent entropy-driven amplification.
• Strand displacement reactions separate a FRET pair, leading to amplified FAM fluorescence.

Main Results:

• Achieved ultra-sensitive detection of microRNA-21 with a limit of detection (LOD) of 1.3 fM.
• The cascade strategy demonstrated a 100-fold improvement in sensitivity compared to CHA alone.
• Successfully quantified microRNA-21 in human serum and cell lysates, confirming practical applicability.

Conclusions:

• The developed enzyme-free fluorescence biosensor offers ultra-sensitive microRNA-21 detection.
• The cascade amplification strategy provides a significant advancement over existing methods.
• This biosensor holds great potential for early clinical diagnosis and disease monitoring.