SARS-CoV-2 Point-of-Care (POC) Diagnosis Based on Commercial Pregnancy Test Strips and a Palm-Size Microfluidic Device

Abstract

Coronavirus diseases such as the coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), pose serious threats. Portable and accurate nucleic acid detection is still an urgent need to achieve on-site virus screening and timely infection control. Herein, we have developed an on-site, semiautomatic detection system, aiming at simultaneously overcoming the shortcomings suffered by various commercially available assays, such as low accuracy, poor portability, instrument dependency, and labor intensity. Ultrasensitive isothermal amplification [i.e., reverse transcription loop-mediated isothermal amplification (RT-LAMP)] was applied to generate intensified SARS-CoV-2 RNA signals, which were then transduced to portable commercial pregnancy test strips (PTSs) via ultraspecific human chorionic gonadotropin (hCG)-conjugated toehold-mediated strand exchange (TMSE) probes (hCG-P). The entire detection was integrated into a four-channel, palm-size microfluidic device, named the microfluidic point-of-care (POC) diagnosis system based on the PTS (MPSP) detection system. It provides rapid, cost-effective, and sensitive detection, of which the lowest concentration of detection was 0.5 copy/μL of SARS-CoV-2 RNA, regardless of the presence of other similar viruses, even highly similar severe acute respiratory syndrome coronavirus (SARS-CoV). The successful detection of the authentic samples from different resources evaluated the practical application. The commercial PTS provides a colorimetric visible signal, which is instrument- and optimization-free. Therefore, this MPSP system can be immediately used for SARS-CoV-2 emergency detection, and it is worthy of further optimization to achieve full automation and detection for other infectious diseases.

Recent advances of functional nucleic acid-based sensors for point-of-care detection of SARS-CoV-2

“…While all the above devices offer rapid sample-to-result diagnostics, their lack of portability may make them unaffordable by the majority of users within resource-limited environments. Motivated by the cost of diagnostics, a semiautomated field assay was developed via a human chorionic gonadotropin-conjugated toehold-mediated strand exchange probe, which was conducted onto a portable commercial pregnancy test strip [ 19 ]. The Internet of Things-based reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) POC device analyzes three target genes (As1e, N, and E genes) of SARS-CoV-2 to prevent false-positive results [ 20 ].…”

Microfluidics Technology in SARS-CoV-2 Diagnosis and Beyond: A Systematic Review

“…Li et al developed CRISPR-based recognition SARS-CoV-2 amplified gene by RPA in a microfluidic chamber and AuNP conjugated lateral-flow system for detection. The naked eye can detect SARS-CoV-2 nucleic acids [ 107 , 108 ]. The whole detection process of SARS-CoV-2 in Yang et al’s developed assay took less than 2 h with a limit of detection of 0.5 copy/µL and was validated by diagnosing one clinical authenticated swab sample from a COVID-19-positive patient and 16 negative samples [ 107 ].…”

“…The naked eye can detect SARS-CoV-2 nucleic acids [ 107 , 108 ]. The whole detection process of SARS-CoV-2 in Yang et al’s developed assay took less than 2 h with a limit of detection of 0.5 copy/µL and was validated by diagnosing one clinical authenticated swab sample from a COVID-19-positive patient and 16 negative samples [ 107 ]. On the contrary, the detection limit in Li et al developed assay is 100 copies of RNA per target.…”

“…Among fluid manipulation techniques, centrifugal force was the most commonly used strategy, followed by electrochemical pumping, capillary action, manual pipetting, hydrostatic pressure, isotachophoresis, and syringe pump [ 82 , 84 , 85 , 94 , 102 , 104 , 105 , 109 ]. Yang et al used manual pipetting followed by capillary action for the fluid manipulation strategy [ 107 ].…”

Design and simulation of a millifluidic device for differential detection of SARS-CoV-2 and H1N1 based on triboelectricity

“…Aside from clinical detection methods, micro-total analysis systems (μ-TAS) such as point-of-care (PoC) devices emerged to achieve lab-on-a-chip technology; accordingly, antigen/antibody rapid detection tests have evolved the biosensor industry in virtue of low sample requirement, portable and high-throughput detection, easy-to-operate, cost- and time-effective monitoring of health conditions, and great accessibility on the user's end with comparable accuracy and sensitivity [8] . Early PoC diagnosis based on nucleic acid tests, immunoassays and state-of-the-art biosensors is thus conducive to epidemic control and timely treatment [9] , [10] , [11] .…”