A miniaturized RPA-CRISPR/Cas12a-based nucleic acid diagnostic platform for rapid and simple self-testing of SARS-CoV-2.

Nucleic acid testing is the most effective detection method currently available for the diagnosis of respiratory infectious diseases. However, the conventional real-time fluorescent quantitative PCR technique, which is regarded as the gold standard method for nucleic acid detection, presents significant challenges for implementation in home self-testing and popularization in underdeveloped regions due to its rigorous experimental standards. It is therefore clear that an easy-to-use, miniaturized nucleic acid testing technology and products for nonprofessionals are of great necessity to define the pathogens and assist in controlling disease transmission. (87) RESULTS: In this study, we propose a strategy for self-testing of respiratory pathogen nucleic acid that is oriented towards the public and user-friendly. The proposed system integrates the processes of extraction-free nucleic acid release, RPA isothermal amplification, and CRISPR fluorescence detection into a compact configuration. A microfluidic testing chip actuated by air pouches and a battery/USB-powered reusable device has been developed to enable simultaneous detection of internal reference genes and viral targets in a fully enclosed condition. The system allows for sample-in, and result-out testing in less than 30 min with a detection limit of 2 copies/μL. Additionally, a straightforward signal-light-based result display method has been developed to make it easy and intuitive for users to access the results. Furthermore, freeze-drying reagent is introduced to guarantee the storage and transportation of testing chips in ambient conditions. (135) SIGNIFICANCE: This work presents a miniaturized, portable, and highly sensitive nucleic acid detection system, where simple operating procedures have been designed for unskilled users. It is our belief that the testing system developed in this work is well suited for home-based self-testing and infection diagnosis in resource-limited areas, due to the above-mentioned advantages. (52).