Research / 2021 / Article / Fig 1

Research Article

Low-Cost and Scalable Platform with Multiplexed Microwell Array Biochip for Rapid Diagnosis of COVID-19

Figure 1

System setup of the portable instrument and multiplexed microwell array biochip based on RT-LAMP for point-of-care testing of SARS-CoV-2. (a) The designed portable detection instrument with labelled parts: (I) the area for loading human tissue sampling and preservation in a small sampling tube—patients collect their own tissue sample through pharyngeal swab; (II) the zone for total RNA extraction—preserved samples are transferred for inactivation and RNA extraction in virus lysis buffer using a custom-made three-channel pipette; (III) multiplexed microwell array biochip for RT-LAMP reaction—top view of the microwell device with a detection zone and control zone, which detects three clinical samples. The BRAC1 gene is used as the positive control, and ddH2O is used as the negative control; (IV) display module of the detector—all detection results and parameter settings are integrated on the liquid crystal display of the instrument. (b) The schematic of a RT-LAMP biochip for simultaneous detection of multiple samples. For testing, RNA samples are added into the microwell prefilled with our designed LAMP solution. The amplification reaction, occurring at 60°C, leads to a colorimetric change in the solution that can be visualized by the digital image sensor or with the naked eye. The microwells for RNA amplification were engraved with a commercial laser system. The microwell designed in conical shape was demonstrated to speed up the amplification as compared to commercial PCR tubes. (c) The genome map shows the LAMP primers targeting at the ORF1ab gene of the SARS-CoV-2. The inner primers (FIP and BIP) consist of two distinct parts of target, F2+F1c and B2+B1c, respectively. The loop primers (LoopF and LoopB) are designed by using the complementary strands according to the fragments between F1 and F2, or B1c and B2c.