Self-Powered Biosensor Based on DNA Walkers for Ultrasensitive MicroRNA Detection

Area of Science:

• Biosensor technology
• Electrochemical biosensing
• Nucleic acid detection

Background:

• MicroRNA-21 (miRNA-21) is a biomarker for various diseases.
• Ultrasensitive and selective detection of miRNA-21 is crucial for early diagnosis.
• Existing detection methods often require complex procedures and external power sources.

Purpose of the Study:

• To develop a novel self-powered biosensor for ultrasensitive miRNA-21 detection.
• To utilize DNA walkers and an enzymatic biofuel cell (EBFC) for signal amplification.
• To demonstrate the biosensor's capability in detecting miRNA-21 in human serum.

Main Methods:

• Fabrication of a self-powered biosensor integrating an EBFC, DNA walkers, a digital multimeter (DMM), and a capacitor.
• Employing DNA walkers on the cathode for signal amplification.
• Utilizing the capacitor to store electrochemical energy from the EBFC for enhanced current detection.
• Investigating the mechanism of miRNA-21 binding and its effect on electrochemical signals.

Main Results:

• The biosensor achieved ultrasensitive detection of miRNA-21 in the range of 0.5 to 10^4 fM.
• A low detection limit of 0.15 fM for miRNA-21 was obtained.
• The biosensor demonstrated high selectivity for miRNA-21 detection in human serum samples.
• The self-powered nature of the biosensor eliminated the need for external power.

Conclusions:

• The developed self-powered biosensor offers a promising platform for ultrasensitive and selective miRNA-21 detection.
• The combination of DNA walkers and EBFC provides an effective signal amplification strategy.
• This biosensor has potential applications in early disease diagnosis and biomedical monitoring.