Nonenzymatic DNA-Based Fluorescence Biosensor Combining Carbon Dots and Graphene Oxide with Target-Induced DNA Strand...

Area of Science:

• Biotechnology
• Nanotechnology
• Molecular Biology

Background:

• MicroRNAs (miRNAs) are crucial regulators of gene expression.
• Accurate detection of miRNAs is vital for disease diagnosis and biological research.
• Existing miRNA detection methods can be complex and time-consuming.

Purpose of the Study:

• To develop a simple, highly sensitive, and rapid fluorescence biosensor for miRNA detection.
• To utilize carbon dots (CDs) and graphene oxide (GO) for enhanced sensing capabilities.
• To achieve signal amplification through a recyclable target-induced mechanism.

Main Methods:

• Fabrication of a DNA-based fluorescence biosensor using CDs and GO.
• Employing a fluorescence "on-off-on" strategy based on strand displacement reactions.
• Utilizing toehold-mediated strand displacement on DNA-modified gold nanoparticles for signal amplification.

Main Results:

• Successful synthesis and conjugation of CDs to DNA on GO surface, leading to fluorescence quenching.
• Restoration of fluorescence upon introduction of target miRNA let-7a via a recyclable mechanism.
• Demonstrated a good linear relationship between fluorescence intensity and let-7a concentration (0.01-1 nM) with a low detection limit (7.8 pM).

Conclusions:

• The developed biosensor is simple, highly sensitive, and efficient for miRNA detection.
• The "on-off-on" fluorescence strategy and signal amplification offer advantages for biosensing.
• This approach has potential for detecting various miRNAs and designing improved biosensors.