SNAPflex: a paper-and-plastic device for instrument-free RNA and DNA extraction from whole blood

Nucleic acid amplification tests (NAATs), which amplify and detect pathogen nucleic acids, are vital methods to diagnose diseases, particularly in cases where patients exhibit low levels of infection. For many blood-borne pathogens such as HIV or Plasmodium, it is necessary to first extract pathogen RNA or DNA from patient blood prior to analysis with NAATs. Traditional nucleic acid extraction methods are expensive, resource-intensive and are often difficult to deploy to resource-limited areas where many blood-borne infections are widespread. Here, we describe a portable, paper-and-plastic device for instrument-free nucleic acid extraction from whole blood, which we call SNAPflex, that builds upon our previous work extracting RNA in a 2D platform from nasopharyngeal swabs. We demonstrated improved extraction of HIV RNA from simulated patient samples compared to traditional extraction methods and long-term stability of extracted RNA without the need for cold storage. We further demonstrated successful extraction and recovery of Plasmodium falciparum DNA from simulated patient samples with superior recovery compared to existing extraction methods. The SNAPflex device extracts and purifies DNA and RNA from whole blood which can be amplified with traditional NAATs, and was designed to easily manufacture and integrate into existing health systems.