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In June 2020, engineers at the University of California San Diego published a paper demonstrating the prospect of using "nanosponges" to fight against severe acute respiratory syndrome coronavirus 2 (COVID-19). This innovation was tested by researchers at Boston University.
Since it was detected in Wuhan, China, in December 2019, COVID-19 has turned into a severe international health crisis. At the time of this writing, the WHO (World Health Organization, 2020) has recorded around 16.3 million confirmed cases worldwide. With the medical professionals confirming that the virus damages other vital organ systems of the patients, researchers around the world are wasting no time and working diligently hard to find a vaccine.
On 27th July, WHO published the current draft landscape of COVID-19 candidate vaccines (World Health Organization, 2020). Their record shows that there are currently 25 candidate vaccines in clinical evaluation and 139 candidate vaccines in preclinical evaluation. A recent distinguishable finding is the use of nanoparticle-based polymers called "nanosponges" to protect healthy cells instead of targeting the virus itself (Zhang, et al., 2020).
Can Nanoparticles Treat COVID-19 Patients?
Nanoparticles have gained a prestigious reputation in the medical sector as one of the mediums for drug delivery.
As the nanoparticles can be tailored according to size and surface characteristics, they can be developed into smart mediums to deliver drugs to specific tissues while refraining the drug-related toxicity (Rizvi & Saleh).
According to the researchers, the small size and large surface area properties of nanoparticles enhance their solubility and ability to cross the blood-brain barrier.
Since the pandemic has unfolded, the field of nanomedicine has been analyzing nanoparticles as a prospective promising medium to treat infected patients.
COVID-19 is estimated to have a diameter of around 125 nm, which could be easily detected and neutralized by biocompatible nanoparticles (Itani, Tobaiqy, & Faraj, 2020). The choice of polymer-based nanoparticles offers drug stability with smart release properties while effectively delivering drugs directly to the targeted site (Bennet & Kim).
The antimicrobial properties of polymers with metal nanoparticles have been common studies to understand their combined properties (van Doremalen, et al., 2020). Plaza (Palza, 2015) demonstrated that the addition of metal nanoparticles, such as silver or copper, into the polymer, shows a strong signal of producing biocide materials, including the higher release of metal ions that confirms the antimicrobial behavior.
At the initial stage of the pandemic, the US was experimenting with Remdesivir as an antiviral drug for COVID-19, although the result did not show significant improvements in mortality rates or patient recovery (Wang, et al., 2020).
In Europe, the Prague Public Transit Company tested titanium-dioxide nano polymer-based disinfectants that can kill 99.9% of any virus or bacteria (Dopravni podnik hlavniho mesta Prahy, 2020).
However, the challenge of finding new drugs or vaccines remained and required a clear perspective of the underlying molecular mechanisms of the virus.
The biomimetic nanosponge platform introduced by Zhang and co. to fight COVID-19 was created more than a decade ago and has currently been under development for a wide range of applications.
The nanosponges soak up harmful pathogens and toxins, and are 1000 times smaller than the width of a human hair. They feature a biodegradable, FDA-approved polymer core coated in a specific type of cell membrane that can be disguised as a red blood cell, an immune T cell, or a platelet cell (Zhang, et al., 2020).
Click here to find out more about different nanoparticle characterization systems
How do Nanosponges Work?
The cellular nanosponges consist of two types of cores; human lung epithelial type II cell and human macrophage, made from poly(lactic-co-glycolic acid) (PLGA) sonicated to form Epithelial-NS and MΦ-NS, respectively.
The cladding is the natural cell membranes from target cells. The virus is believed to enter the body through the nose, mouth or eyes. It attaches to a protein called ACE2 (Corum & Zimmer, 2020) found in epithelial cells of lungs, heart, blood vessels, kidneys liver, and gastrointestinal tract.
By covering the polymer-nanoparticles core with the outer membranes of lung epithelial cells, the virus could be tricked into it and prevent them from entering human cells. The result demonstrated significant advantages of MΦ-NS over Epithelial-NS to neutralize the COVID-19, although both types of cores showed positive results in a dose-dependent manner as long as the virus targets the identified host cell.
Find out more: Nanomaterials available on the market today
Future Development of Nanosponges
Although the nanosponges are proven to block a high percentage of the virus’s ability to enter human cells, they still need to pass the safety criteria in humans.
The animal model validation is currently under investigation, after which the human clinical trials will begin. Upon successful completion of the test, the nanosponges are expected to work against COVID-19 as well as any new coronavirus or other respiratory viruses.
References and Further Reading
Bennet, D., & Kim, S. (2014). Polymer Nanoparticles for Smart Drug Delivery. In Application of Nanotechnology in Drug Delivery. https://www.intechopen.com/books/application-of-nanotechnology-in-drug-delivery/polymer-nanoparticles-for-smart-drug-delivery
Corum, J., & Zimmer, C. (2020). How Coronavirus Hijacks Your Cells. [Online] The New York Times. Available at: https://www.nytimes.com/interactive/2020/03/11/science/how-coronavirus-hijacks-your-cells.html (Accessed on 28 July 2020).
Dopravni podnik hlavniho mesta Prahy. (2020). DPP to disinfect its entire fleet of public transport vehicles using nanotechnology-based polymers. This disinfecting coating is projected to last for up to two years. [Online] Dopravni podnik hlavniho mesta Prahy. Available at: https://www.dpp.cz/en/company/for-media/press-news/detail/580_1078-dpp-to-disinfect-its-entire-fleet-of-public-transport-vehicles-using-nanotechnology-based-polymers-this-disinfecting-coating-is-projected-to-last-for-up-to-two-years (Accessed on 28 July 2020).
Itani, R., Tobaiqy, M., & Faraj, A. A. (2020). Optimizing use of theranostic nanoparticles as a life-saving strategy for treating COVID-19 patients. Theranostics, 10(13), 5932-5942. https://pubmed.ncbi.nlm.nih.gov/32483428/
Palza, H. (2015). Antimicrobial Polymers with Metal Nanoparticles. International journal of molecular sciences, 16(1), 2099-2116. https://doi.org/10.3390/ijms16012099
Rizvi, S. A., & Saleh, A. M. (n.d.). Applications of nanoparticle systems in drug delivery technology. Saudi Pharmaceutical Journal, 26(1). https://doi.org/10.1016/j.jsps.2017.10.012
van Doremalen, N., Bushmaker, T., Morris, D. H., Holbrook, M. G., Gamble, A., Williamson, B. N., . . . Munster, V. J. (2020). Aerosol and Surface Stability of SARS-CoV-2. New England Journal of Medicine, 382(16). https://www.nejm.org/doi/full/10.1056/NEJMc2004973
Wang, Y., Zhang, D., Du, G., Du, R., Zhao, J., Jin, Y., . . . Luo, G. (2020). Remdesivir in adults with severe COVID-19: a randomised, double-blind, placebo-controlled, multicentre trial. The Lancet. https://doi.org/10.1016/S0140-6736(20)31022-9
World Health Organization. (2020). Draft landscape of COVID-19 candidate vaccines. [Online] World Health Organization. Available at: https://www.who.int/publications/m/item/draft-landscape-of-covid-19-candidate-vaccines (Accessed on 28 July 2020).
World Health Organization. (2020). WHO Coronavirus Disease (COVID-19) Dashboard. [Online] World Health Organization. Available at: https://covid19.who.int/ (Accessed on 28 July 2020).
Zhang, Q., Honko, A., Zhou, J., Gong, H., Downs, S. N., Vasquez, J. H., Zhang, L. (2020). Cellular Nanosponges Inhibit SARS-CoV-2 Infectivity. Nano Letters. https://doi.org/10.1021/acs.nanolett.0c02278