A simple and innovative sample preparation method for on-site SARS-CoV-2 molecular diagnostics

Nucleic acid amplification is a widely used diagnostic tool, although it requires a relatively time-consuming and complicated extraction step. To address this issue outside the laboratory, we investigated a sample preparation system, and determined that silica membrane and silica-coated magnetic beads are powerful tools for extraction from raw samples: nucleic acids are kept in the silica membrane, retained during a single wash step, and released at the elution step. The eluent is appropriate for quantitative real-time polymerase chain reaction (qPCR) and loop-mediated amplification (LAMP) assay in terms of purity and quantity. We also built an innovative equipment-free nucleic acid extraction squeeze system and it requires less than 20 min. The sample with improved purity augments the specificity and sensitivity. This system is simple, user-friendly, low-cost, and equipment-free, thus making nucleic acid extraction more accessible and affordable for researchers and untreated persons. Furthermore, when combined with reverse transcription-quantitative real-time polymerase chain reaction method, the method will accelerate the detection of diseases. The same goes when combined with the LAMP assay, especially in developing countries.