An isolation-free smartphone-based saliva assay can diagnose COVID-19 cases and quantify viral load within 15 min. Point-of-care COVID-19 assays that are more sensitive than the current RT-PCR (reverse transcription polymerase chain reaction) gold standard assay are needed to improve disease control efforts. We describe the development of a portable, ultrasensitive saliva-based COVID-19 assay with a 15-min sample-to-answer time that does not require RNA isolation or laboratory equipment. This assay uses CRISPR-Cas12a activity to enhance viral amplicon signal, which is stimulated by the laser diode of a smartphone-based fluorescence microscope device. This device robustly quantified viral load over a broad linear range (1 to 10 5 copies/μl) and exhibited a limit of detection (0.38 copies/μl) below that of the RT-PCR reference assay. CRISPR-read SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) RNA levels were similar in patient saliva and nasal swabs, and viral loads measured by RT-PCR and the smartphone-read CRISPR assay demonstrated good correlation, supporting the potential use of this portable assay for saliva-based point-of-care COVID-19 diagnosis.
【초록키워드】 COVID-19, SARS-CoV-2, Saliva, coronavirus, equipment, severe acute respiratory syndrome Coronavirus, RT-PCR, Laboratory, RNA, CRISPR, reverse transcription polymerase chain reaction, polymerase chain reaction, point-of-care, Viral, Viral load, disease control, Patient, COVID-19 diagnosis, limit of detection, Smartphone, gold, reverse transcription, respiratory, correlation, disease, diagnose, COVID-19 cases, Microscope, Chain Reaction, acute respiratory syndrome, fluorescence microscope, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, COVID-19 case, gold standard, viral loads, nasal swabs, RNA isolation, polymerase chain, ENhance, IMPROVE, stimulated, linear, exhibited, demonstrated, quantified, 【제목키워드】 COVID-19, Quantitative, saliva test,