Photoelectrochemical biosensor for microRNA detection based on multiple amplification strategies

Area of Science:

• Biosensors and electrochemical detection
• Biomolecular analysis
• Nanomaterials in sensing

Background:

• MicroRNAs (miRNAs) are crucial biomarkers for various biological processes and diseases.
• Sensitive and specific detection of miRNAs is essential for early diagnosis and research.
• Existing detection methods often require complex procedures or lack sufficient sensitivity.

Purpose of the Study:

• To develop a highly sensitive photoelectrochemical biosensor for microRNA-162a detection.
• To implement a multiple amplification strategy for enhanced signal transduction.
• To validate the biosensor's performance in analyzing biological samples.

Main Methods:

• Utilized graphite-like carbon nitride (g-C3N4) nanosheets as the photoactive material.
• Employed a multi-step amplification strategy including isothermal strand displacement polymerase reaction and terminal deoxynucleotidyl transferase-mediated extension.
• Incorporated streptavidin-coated gold nanoparticles and biotin-functionalized alkaline phosphatase for signal enhancement.

Main Results:

• Achieved an ultra-low detection limit of 0.18 femtomolar (fM) for microRNA-162a.
• Demonstrated a linear relationship between photocurrent and microRNA-162a concentration from 0.5 fM to 1 picomolar (pM).
• Successfully quantified microRNA-162a levels in total RNA from maize seedlings treated with ethyl methanesulfonate.

Conclusions:

• The developed photoelectrochemical biosensor offers high sensitivity and specificity for microRNA detection.
• The multiple amplification strategy significantly enhances detection performance.
• The method is applicable for analyzing microRNA expression in practical biological samples, showing potential for diagnostic applications.