Novel fluorescence nano-orbital biosensor for highly sensitive microRNA detection

Area of Science:

• Biochemistry
• Molecular Biology
• Biotechnology

Background:

• MicroRNAs are crucial regulators of cellular function and gene expression.
• Accurate detection of microRNAs is vital for early disease diagnosis and prevention.
• Traditional methods struggle with low-abundance, small-molecule microRNAs due to limitations in sensitivity and sample requirements.

Purpose of the Study:

• To develop a novel biosensor for ultrasensitive and accurate microRNA detection.
• To overcome the limitations of traditional microRNA detection methods.
• To establish a fluorescence-based signal amplification system for microRNA recognition.

Main Methods:

• Designed an E-NOF biosensor utilizing an exponential amplification reaction (EXPAR) with cascaded HCR and DNAzyme nucleic acid circuits.
• Constructed fluorescence nano-orbitals (NOF) triggered by amplicon sub-fragments.
• Incorporated dual fluorophores (Cy3 and Cy5) for fluorescence resonance energy transfer (FRET) signal generation and ratio analysis.

Main Results:

• The E-NOF biosensor achieved ultrasensitive detection of microRNA across a wide dynamic range (1 fM to 100 nM).
• The detection limit was as low as 0.129 fM, representing a 10^9-fold increase in sensitivity over traditional HCR systems.
• The biosensor demonstrated rapid detection within 120 minutes and validated its efficacy in human serum samples.

Conclusions:

• The E-NOF biosensor represents a pioneering strategy for microRNA detection by cascading EXPAR, HCR, and DNAzyme circuits.
• This novel biosensor offers significantly enhanced sensitivity and accuracy for microRNA detection compared to existing methods.
• The E-NOF biosensor shows substantial potential for clinical applications in microRNA-based diagnostics and biomarker identification.