The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread to almost every corner of the world, causing social instability. The disease resulting from the coronavirus 2019 (COVID-19) causes fever, sore throat, cough, pain in the chest and muscles, dyspnea, confusion, anosmia, ageusia and headache.
These can progress to life-threatening respiratory failure, which also affects the heart, kidneys, liver, and nervous systems. The diagnosis of SARS-CoV-2 infection is often confused with that of influenza and seasonal upper respiratory tract viral infections. Due to the treatment strategies available and the containment required, a rapid diagnosis is required.
This review brings clarity to the rapidly growing body of available and developing diagnostic tests, including nanomaterial-based tools. It serves as a resource guide for scientists, physicians, students, and the general public.
Within a few months, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified as the etiologic agent of coronavirus disease 2019 (COVID-19). Weeks later, viral diagnostic measures were implemented1. This served to supplement the signs and symptoms of the common COVID-19 illness of cough, fever, and dyspnea. As all are seen during seasonal upper respiratory tract infections, 2 accurate diagnostic tests are required to detect viral nucleic acids, viral antigens, or serological tests to confirm SARS-CoV-23 infection.
Chest computed tomography (CT) or magnetic resonance imaging (MRI) confirm the manifestations of the disease2,3. The signature of COVID-19 is the life-threatening acute respiratory distress syndrome (ARDS) 4. Although the lung is the main viral target, the cardiovascular, brain, kidney, liver, and immune systems are often affected by infections5.
Thus, due to the significant morbidity and mortality of COVID-19, containment of viral transmission was implemented through contact tracing, clinical evaluation, and virus detection through social distancing, masks, contact isolation, and hand hygiene to limit transmission. of SARS-CoV-26.
SARS-CoV-2 Detection Overview
The first step in the management of COVID-19 is the rapid and accurate detection of SARS-CoV-2 using the real-time reverse transcription-polymerase chain reaction (RT-PCR) 7. RT-PCR detects acids SARS-CoV-2 nucleic agents present in nasopharyngeal fluids8.
The tests are used to prevent infectious spread between people and communities that include asymptomatic infected people, whose viral shedding can inadvertently transmit the infection to the elderly and people with comorbidities9. Accurate virus detection is a starting point for containing the COVID-1910 pandemic. The flaws affect public safety, allowing the spread of the infection with the help of false negative test results11.
Improving the sensitivity and specificity of tests remains an urgent need7. Serological tests complement the detection of viruses, indicating a past infection, which could be exploited for therapeutic benefits. Antibodies are detected by enzyme-linked immunosorbent assay using qualitative detection of IgG or IgM12 antibodies. These tests determine an immune response against the viral spike (S) protein and may be useful to assess protection against subsequent viral exposure and/or for contact tracing purposes13.
Therefore, the importance of such tests cannot be overstated. This is also true for epidemiological evaluations and broad global therapeutic needs14. Future work includes the development of diagnostic tests to improve the sensitivity and specificity of immunoassays13. In fact, these tests will ultimately reveal viral protection as reinfections emerge15. Inducing immunity against SARS-CoV-2 is the next frontier for the control of COVID-1915,16.
To this end, our intention in this review is to summarize the clinical presentation of the disease with a focus on how best to implement nanomaterial-based diagnostic tests and other tests at the individual, community, and societal levels. The Review describes current and future nanomaterial diagnostics for COVID-19. The intention is to facilitate the containment of the global spread of the virus12,15.
SARS-CoV-2 Body Fluid and Tissue Distribution
The viral load of SARS-CoV-2 and respiratory tract viral particles parallel the dynamics of the virus in fluids and te