Centrifugal Microfluidic Method for Enrichment and Enzymatic Extraction of Severe Acute Respiratory Syndrome Coronavirus 2 RNA
ABSTRACT: The diversification of analytical tools for diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is imperative for effective virus surveillance and transmission control worldwide. Development of robust methods for rapid, simple isolation of viral RNA permits more expedient pathogen detection by downstream real-time reverse transcriptase polymerase chain reaction (real-time RT-PCR) to minimize stalled containment and enhance treatment efforts. Here, we describe an automatable rotationally driven microfluidic platform for enrichment and enzymatic extraction of SARS-CoV-2 RNA from multiple sample types. The multiplexed, enclosed microfluidic centrifugal device (μCD) is capable of preparing amplification-ready RNA from up to six samples in under 15 min, minimizing user intervention and limiting analyst exposure to pathogens. Sample enrichment leverages Nanotrap Magnetic Virus Particles to isolate intact SARS-CoV-2 virions from nasopharyngeal and/or saliva samples, enabling the removal of complex matrices that inhibit downstream RNA amplification and detection. Subsequently, viral capsids are lysed using an enzymatic lysis cocktail for release of pathogenic nucleic acids into a PCR-compatible buffer, obviating the need for downstream purification. Early in-tube assay characterization demonstrated comparable performance between our technique and a “gold-standard” commercial RNA extraction and purification kit. RNA obtained using the fully integrated μCDs permitted reliable SARS-CoV-2 detection by real-time RT-PCR. Notably, we successfully analyzed full-process controls, positive clinical nasopharyngeal swabs suspended in viral transport media, and spiked saliva samples, showcasing the method’s broad applicability with multiple sample matrices commonly encountered in clinical diagnostics.