Detection of Norovirus Using Paper-Based Cell-Free Systems.

Norovirus infections are the leading cause of foodborne illness and human gastroenteritis, afflicting hundreds of millions of people each year. Molecular assays with the capacity to detect norovirus without expensive equipment and with high sensitivity and specificity represent useful tools to track and contain future outbreaks. Here we describe how norovirus can be detected in low-cost paper-based cell-free reactions. These assays combine freeze-dried, thermostable cell-free transcription-translation reactions with toehold switch riboregulators designed to target the norovirus genome, enabling convenient colorimetric assay readouts. Coupling cell-free reactions with synbody-based viral enrichment and isothermal amplification enables detection of norovirus from clinical samples down to concentrations as low as 270 zM. These diagnostic tests are promising assays for confronting norovirus outbreaks and can be adapted to a variety of other human pathogens.