Integrated microdroplet array platform with temperature controller and micro-stirring for ultra-fast SARS-CoV-2 detection

The outbreak of COVID-19 has created a huge challenge to global health systems. Experience in fighting the epidemic shows that the development of a rapid and sensitive POCT diagnostic platform for SARS-CoV-2 that can be deployed in situ is crucial to contain the outbreak. Here, we have developed a portable microdroplet detection platform that integrated temperature controller and micro-stirring for high-throughput and ultrafast COVID-19 diagnosis. Such a device uses a p-n junction (PN junction) as the temperature controller to adjust the temperature in a single microdroplet independently and precisely, ensuring the amplification of reverse transcription loop-mediated isothermal amplification (RT-LAMP). Meanwhile, the platform incorporates an ultrasonic micro-stirring unit, greatly increasing the interaction between RT-LAMP molecules and accelerating the amplification. The results show good linearity over a wide linear range (1 to 10(5) copies/μL) and low LOD (0.48 copy/μL). Our method reports in only 6.1 min for high-viral load samples, and combines with sample preparation, the total detection process could be done within 30 min. Such a portable and fully integrated microdroplet molecular diagnostic platform is a promising tool for point-of-care diagnosis of COVID-19 and other infectious diseases in resource-limited settings.