Paper-based nucleic acid sample preparation for point-of-care diagnostics

Nucleic acid amplification tests (NAATs) play a crucial role in the early diagnosis and prevention of various infectious diseases. Over the last decade, paper-based devices have garnered attention as low-cost devices for conducting NAATs at the point-of-care (POC). Sample preparation is a critical and one of the most cumbersome steps in a NAAT. We present a comprehensive review of paper-based nucleic acid (NA) sample preparation techniques that have been developed for various complex sample types. We project NAATs as a series of three-unit operations – lysis, purification, and amplification (lysis and purification together constitute the process of sample preparation). Any one or all three operations could be conducted in paper, resulting in multiple possible workflows. We categorize all published paper-based NA sample preparation strategies into one of these workflows, thus presenting a new way to rationally categorize the numerous paper-assisted NA sample preparation workflows. Towards the end, we present a perspective on progress in the field and conclude by enlising important gaps in the area to guide future research.