Diagnostic assay and technology advancement for detecting SARS-CoV-2 infections causing the COVID-19 pandemic

Abstract

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-caused COVID-19 pandemic has transmitted to humans in practically all parts of the world, producing socio-economic turmoil. There is an urgent need for precise, fast, and affordable diagnostic testing to be widely available for detecting SARS-CoV-2 and its mutations in various phases of the disease. Early diagnosis with great precision has been achieved using real-time polymerase chain reaction (RT-PCR) and similar other molecular methods, but theseapproaches are costly and involve rigorous processes that are not easily obtainable. Conversely, immunoassays that detect a small number of antibodies have been employed for quick, low-cost tests, but their efficiency in diagnosing infected people has been restricted. The use of biosensors in the detection of SARS-CoV-2 is vital for the COVID-19 pandemic's control. This review gives an overview of COVID-19 diagnostic approaches that are currently being developed as well as nanomaterial-based biosensor technologies, to aid future technological advancement and innovation. These approaches can be integrated into point-of-care (POC) devices to quickly identify a large number of infected patients and asymptomatic carriers. The ongoing research endeavors and developments in complementary technologies will play a significant role in curbing the spread of the COVID-19 pandemic and fill the knowledge gaps in current diagnostic accuracy and capacity.

Keywords: Biosensors; COVID-19; Detection; Immunoassays; Molecularassays; SARS-CoV-2 infections.

Fig. 1

WHO reports weekly COVID-19 cases and deaths by region [4]

Fig. 2

The origins of human coronaviruses in animals. Adapted from Rabi et al., licensed CC BY 4.0 (2020) [15].

Fig. 3

The overall structure of SARS-CoV-2 is seen in this diagram. A The viral surface proteins such as spike protein (S), small envelope protein (E), and membrane protein (M) are embedded in a lipid bilayer envelope generated from the host cell. Inside the viral envelope is single-stranded positive-sense viral RNA coupled with the nucleocapsid protein (N) (above). B The RNA genome includes 5′ and 3′ untranslated regions (UTRs), a 5′ methylated cap (ME), and a 3′ poly-A tail. The genes that code for non-structural proteins (Nsp) and spike (S), membrane (M), envelope (E), and nucleocapsid (NC) proteins are shown in the diagram (below).

Fig. 4

The most studied detection approaches along the trajectory of infection for SARS-CoV-2. The figure depicts the dynamic range of SARS-CoV-2 infectivity, viral RNA, and host immunoglobulins (IgM and IgG), as well as COVID-19, time kinetics. Upon hitting a measurable level in blood, antibodies undergo seroconversion. Note: The amounts of each antibody shown in this chart are for illustration purposes only and do not represent actual values. This is an exemplary design, and it should be noted that there are variations in the literature, particularly for the slope tails. We chose to preserve the excellence and quality until more data was gathered and a consensus is reached on the time courses.

Fig. 5

An overview of the most important detection approaches with their major characteristics

Fig. 6

A quick look at the fast diagnostic serological test. Colorimetric lateral flow immunoassay (LFIA). Reproduced with permission from Ghaffari, A. et al. Copyright MDPI (2020), Diagnostics [108]

Fig. 7

Point-of-care (POC) for COVID-19. Reprinted with permission from Choi, J. et al. Development of point-of-care biosensors for COVID-19. Front Chem 8: 517. Copyright (2019) Frontiers in Chemistry [159].