The recent Zika virus outbreak highlights the need for low-cost diagnostics that can be rapidly developed for distribution and use in pandemic regions. Here, we report a pipeline for the rapid design, assembly, and validation of cell-free, paper-based sensors for the detection of the Zika virus RNA genome. By linking isothermal RNA amplification to toehold switch RNA sensors, we detect clinically relevant concentrations of Zika virus sequences and demonstrate specificity against closely related Dengue virus sequences. When coupled with a novel CRISPR/Cas9-based module, our sensors can discriminate between viral strains with single-base resolution. We successfully demonstrate a simple, field-ready sample-processing workflow and detect Zika virus from the plasma of a viremic macaque. Our freeze-dried biomolecular platform resolves important practical limitations to the deployment of molecular diagnostics in the field and demonstrates how synthetic biology can be used to develop diagnostic tools for confronting global health crises. PAPERCLIP.

Mitigating global infectious disease requires diagnostic tools that are sensitive, specific, and rapidly field-deployable. Here, we demonstrate that the Cas13-based SHERLOCK (Specific High Sensitivity Enzymatic Reporter UnLOCKing) platform can detect Zika virus (ZIKV) and dengue virus (DENV) in patient samples at concentrations down to 1 copy/μl. We develop HUDSON (Heating Unextracted Diagnostic Samples to Obliterate Nucleases), a protocol that pairs with SHERLOCK for viral detection directly from bodily fluids, enabling instrument-free DENV detection directly from patient samples in < 2 hours. We further demonstrate that SHERLOCK can distinguish the 4 DENV serotypes as well as region-specific strains of ZIKV from the 2015–2016 pandemic. Finally, we report the rapid design and testing (<1 week) of instrument-free assays to detect clinically relevant viral single nucleotide polymorphisms.

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