A norovirus detection architecture based on isothermal amplification and expanded genetic systems

Area of Science:

• Molecular biology
• Virology
• Biotechnology

Background:

• Noroviruses are a leading cause of viral gastroenteritis globally.
• Rapid diagnostic tests are needed to prevent norovirus spread.
• Existing tests face challenges with background noise from adventitious nucleic acids (xNA) in biological samples.

Purpose of the Study:

• To develop a rapid, sensitive molecular assay for norovirus detection.
• To overcome background noise issues in complex biological samples like feces.
• To create a point-of-care test with minimal equipment requirements.

Main Methods:

• Integration of artificially expanded genetic information systems (AEGIS) with loop-mediated isothermal amplification (LAMP).
• AEGIS nucleotides were incorporated into primers and molecular beacon stems to reduce background noise.
• RNase H nicking was employed during amplification for enhanced sensitivity.
• Assay validation using fecal samples spiked with murine norovirus (MNV).

Main Results:

• The AEGIS-RT-LAMP assay successfully amplified norovirus RNA from stool samples.
• Detection of as few as 10 copies of noroviral RNA was achieved.
• A fluorescent signal, visible to the human eye, indicated a positive result.
• The assay operated in a closed-vessel system, minimizing contamination risks.

Conclusions:

• The developed AEGIS-RT-LAMP assay offers a sensitive and rapid method for norovirus detection in clinical samples.
• This approach effectively reduces background noise, improving diagnostic accuracy.
• The assay's simplicity and minimal equipment needs make it suitable for resource-limited settings and early diagnosis.