A lab-on-a-chip for the concurrent electrochemical detection of SARS-CoV-2 RNA and anti-SARS-CoV-2 antibodies in saliva and plasma

Abstract

Rapid, accurate and frequent detection of the RNA of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) and of serological host antibodies to the virus would facilitate the determination of the immune status of individuals who have Coronavirus disease 2019 (COVID-19), were previously infected by the virus, or were vaccinated against the disease. Here we describe the development and application of a 3D-printed lab-on-a-chip that concurrently detects, via multiplexed electrochemical outputs and within 2 h, SARS-CoV-2 RNA in saliva as well as anti-SARS-CoV-2 immunoglobulins in saliva spiked with blood plasma. The device automatedly extracts, concentrates and amplifies SARS-CoV-2 RNA from unprocessed saliva, and integrates the Cas12a-based enzymatic detection of SARS-CoV-2 RNA via isothermal nucleic acid amplification with a sandwich-based enzyme-linked immunosorbent assay on electrodes functionalized with the Spike S1, nucleocapsid and receptor-binding-domain antigens of SARS-CoV-2. Inexpensive microfluidic electrochemical sensors for performing multiplexed diagnostics at the point of care may facilitate the widespread monitoring of COVID-19 infection and immunity.

Recent advancements in nucleic acid detection with microfluidic chip for molecular diagnostics

“…Reproduced with permission from Ref. [ 22 ]. (D) A face mask with a lyophilized CRISPR sensor and a colorimetric sensing platform for wearable, noninvasive detection of SARS-CoV-2.…”

“…The highly miniaturized microfluidic technology can integrate complex nucleic acid detection processes on one chip [ 13 , 14 ], which lessens the complexity of the operation and helps build an automatic and efficient diagnosis system [ [15] , [16] , [17] , [18] ]. Various microfluidic chips have been developed to detect nucleic acid [ [19] , [20] , [21] , [22] ]. A series of new nucleic acid detection technologies have been developed in the past two years with the vast demand for the detection of COVID-19 [ [23] , [24] , [25] , [26] ].…”

Emerging Multiplex Nucleic Acid Diagnostic Tests for Combating COVID-19

“…Although this device currently performs only single-plex detection, the multiple reaction chambers within the cartridge suggest multiplexed detection can be achieved. Additionally, it is foreseeable that self-testing may also simultaneously target SARS-CoV-2 RNA and anti-SARS-CoV-2 antibodies, as demonstrated by Najjar et al in a microfluidic device [ 130 ] and by Masterson et al via their nanoplasmonic biosensors [ 131 ]. Wastewater monitoring is an emerging strategy for tracking or even anticipating the dynamics of SARS-CoV-2 infection at the community scale [ 132 , 133 ].…”

Advances in Biosensing Technologies for Diagnosis of COVID-19

“…This device is integrated with Cas12a-based enzymatic detection of SARS-CoV-2 RNA via LAMP and ELISA on the electrode conjugated with RBD of spike S1 protein. This portable, low-cost multiplex electrochemical sensor would be used at the point of care applications for the diagnosis of COVID-19 [ 70 ]. The characteristics of various NAAT used to diagnose COVID-19 are summarized in Table 1 .…”