COVID-19 has changed much of the modern world as we know it. Multiple countries have introduced nationwide lockdowns in order to limit the spread of the disease with far-reaching societal and economic consequences. Another way to combat the disease is to develop scientific diagnosis and therapeutic weapons that can be utilized without the negative consequences, which ultimately follow the partial closing of a country.
Nanotechnology has multiple research areas that can be utilized in this scientific and technological fight against COVID-19: prevention of dissemination and early diagnosis .
COVID-19 is a respiratory virus infection that is transmitted by contact, droplets and passive carriers such as utensils, light switches or handles that share multiple users [2,3]. The immune system is the primary line of defense for most people, but this is not sufficient for people with compromised immune systems . They instead require e.g. hand sanitizers or face masks as a source of protection.
Chemical disinfectants that can be bought in regular stores can be used for disinfection and sterilization. However, they have limited effect over time and pose a potential risk to public health and the environment . A different method has been proposed: metallic nanoparticles [5,6,7].
Metallic nanoparticles are particles of a given metal whose size is on the submicron scale. That is, their diameter is smaller than 0.001 mm (0.00004 inches). This means that their size is comparable to that of a virus particle [8,9]. The interaction between a virus and the nanoparticle depends on which metal is used. One mechanism of action is inactivation of the virus particle before it enters the cells of the human body. The nanoparticle can also stop the viral particle from entering the cell completely [9,10]. This role as an antiviral “doorman” can be due to the binding competition between the virus particle and the nanoparticle – if the nanoparticle binds first, the virus will no longer be able to bind and infect a cell.
The nanoparticles can be incorporated into face masks or can be used for disinfecting air and surfaces to limit the spread of the disease . However, their toxicity must be considered as they can possibly affect human health in larger doses .
Diagnosis on the Nanoscale
It is also important to be able to rapidly and accurately diagnose COVID-19. Control measures such as isolation and infection tracking can be initiated and implemented earlier in each case if the detection and diagnosis process is fast. Nanotechnology in the form of nanomaterials can help increase the accuracy and decrease the testing time for a diagnostic process .
A nanomaterial is any material that exists on the nanoscale. That means that their defining characteristics also depend on their small size. These properties can be e.g. increased strength or reactivity when compared to the same material at a much larger scale . This means that a sphere of gold or silver can be used for different purposes when it is very small (e.g. a nanoparticle) compared to a larger sphere.
Many nanomaterials are already used for virus detection . Nanomaterials can help early detection as they can facilitate the detection of a target (here – an indicator of COVID-19) even if it is present in much smaller concentrations, i.e. at an earlier time in the infection cycle. The implementation of nanomaterials also requires a smaller sample – and possibly less invasive testing. One advantage of nanomaterials is that they can be designed to have specific desired properties such as optical (interaction with light) or magnetic properties. This means that the materials for diagnosis can be designed to promote a faster and more precise diagnosis .
Nanotechnology can aid the fight against the COVID-19 global pandemic. One aspect is to limit the spread of the disease. This can both be with regards to faster diagnosis (and thus earlier onset of control measures) and more efficient protection measures such as face masks or disinfectants. This means that nanotechnology can help limit the dissemination process and lead to less frequent COVID-19 cases. While it might not completely prohibit the virus from spreading, it can slow the disease down while therapeutic measures and vaccines are being developed.
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Note: Featured image by Fusion Medical Animation on Unsplash
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 Subbarao, Kanta, and Siddhartha Mahanty. “Respiratory virus infections: Understanding COVID-19.” Immunity (2020). DOI: https://doi.org/10.1016/j.immuni.2020.05.004
 World Health Organization. “Coronavirus disease (COVID-19): Similarities and differences with influenza”. (2020). https://www.who.int/emergencies/diseases/novel-coronavirus-2019/question-and-answers-hub/q-a-detail/q-a-similarities-and-differences-covid-19-and-influenza
 Talebian, Sepehr, et al. “Nanotechnology-based disinfectants and sensors for SARS-CoV-2.” Nature nanotechnology 15.8 (2020): 618-621. DOI: https://doi.org/10.1038/s41565-020-0751-0
 Rai, Mahendra, et al. “Metal nanoparticles: The protective nanoshield against virus infection.” Critical reviews in microbiology 42.1 (2016): 46-56. DOI: https://doi.org/10.3109/1040841X.2013.879849
 Campos, Estefânia VR, et al. “How can nanotechnology help to combat COVID-19? Opportunities and urgent need.” Journal of Nanobiotechnology 18.1 (2020): 1-23. DOI: https://doi.org/10.1186/s12951-020-00685-4
 Aderibigbe, Blessing Atim. “Metal-based nanoparticles for the treatment of infectious diseases.” Molecules 22.8 (2017): 1370. DOI: https://dx.doi.org/10.3390%2Fmolecules22081370
 Cuffari, Benedette. “The Size of SARS-CoV-2 Compared to Other Things”. (2020). https://www.news-medical.net/health/The-Size-of-SARS-CoV-2-Compared-to-Other-Things.aspx
 Maduray, Kaminee, and Raveen Parboosing. “Metal Nanoparticles: a Promising Treatment for Viral and Arboviral Infections.” Biological trace element research (2020): 1-18. DOI: https://dx.doi.org/10.1007%2Fs12011-020-02414-2
 Brandelli, Adriano, Ana Carolina Ritter, and Flávio Fonseca Veras. “Antimicrobial activities of metal nanoparticles.” Metal Nanoparticles in Pharma. Springer, Cham, 2017. 337-363. DOI: https://doi.org/10.1007/978-3-319-63790-7_15
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