Molecular Beacon Assay Development for Severe Acute Respiratory Syndrome Coronavirus 2 Detection

Area of Science:

• Molecular biology
• Virology
• Diagnostic assay development

Background:

• The rapid spread of SARS-CoV-2 necessitates swift and precise diagnostic tools.
• Existing methods require optimization for speed and accessibility in pandemic scenarios.

Purpose of the Study:

• To develop and validate a molecular beacon (MB)-based assay for SARS-CoV-2 detection.
• To propose a two-stage COVID-19 testing strategy utilizing the developed MB assay.
• To investigate the correlation between MB fluorescence and viral load.

Main Methods:

• Design and optimization of two novel molecular beacons targeting SARS-CoV-2 ORF1ab and S genes.
• Testing of 458 clinical samples (nasopharyngeal and throat swabs) using the MB assay.
• Comparison of MB assay results with commercial RT-PCR, analyzing test duration, sensitivity, and specificity.

Main Results:

• The MB assay demonstrated a strong correlation between higher fluorescence levels and lower cycle threshold (Ct) values from RT-PCR.
• Identified putative G-quadruplex (G4) regions within the SARS-CoV-2 genome.
• The assay achieved a total duration of 2 hours and 20 minutes, including amplification and fluorescence reading.

Conclusions:

• The developed MB assay offers a rapid, simple, and accurate method for detecting SARS-CoV-2 in upper respiratory tract samples.
• The assay's performance suggests its potential utility in clinical diagnostics and public health surveillance for COVID-19.