Electrochemical genosensor based on RNA-responsive human telomeric G-quadruplex DNA: A proof-of-concept with...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Molecular Diagnostics

Background:

• Accurate and sensitive detection of RNA viruses like SARS-CoV-2 is crucial for public health.
• Existing diagnostic methods can be time-consuming or require complex laboratory setups.
• Development of rapid, label-free biosensors is needed for efficient disease surveillance.

Purpose of the Study:

• To develop a facile and label-free electrochemical biosensor for sensitive RNA detection.
• To utilize methylene blue (MB) as a G-quadruplex ligand for signal amplification.
• To demonstrate the biosensor's capability in detecting SARS-CoV-2 RNA.

Main Methods:

• Immobilization of human telomeric G-quadruplex DNA on a transducer.
• Utilizing methylene blue as an electroactive probe that binds to G-quadruplex structures.
• Measuring changes in differential pulse voltammetry (DPV) signal upon target RNA hybridization.
• Assessing sensor performance with synthetic RNA and clinical samples.

Main Results:

• The biosensor achieved a wide linear detection range from 1 zM to 1 μM for synthetic RNA.
• A low limit of detection (LOD) of 0.59 zM for synthetic RNA and 1.4 copy number for plasmid DNA was obtained.
• High selectivity was observed for SARS-CoV-2 RNA over other related coronaviruses (SARS-CoV, MERS-CoV).
• The sensor demonstrated a strong correlation with qRT-PCR for detecting SARS-CoV-2 RNA in clinical specimens.

Conclusions:

• A novel electrochemical RNA biosensor based on MB-G-quadruplex interaction was successfully developed.
• The biosensor provides a sensitive, selective, and label-free platform for SARS-CoV-2 RNA detection.
• This approach holds promise for rapid diagnostics and surveillance of viral infections.