COVID-19 treatment: Study suggests cellular nanosponges could restrict SARS-CoV-2 virus multiplication; animal trials underway
Studies conducted by researchers at UC San Diego showed that cellular nanosponges could reduce the ability of SARS-CoV-2 virus that causes COVID-19 disease to infect host cells
So far, the antiviral medicines that are being used for the treatment of COVID-19 infection target a specific viral species. This makes it difficult to target the SARS-CoV-2 virus as it undergoes mutation. Therefore, in order to form an effective treatment, scientists would have to find out a therapeutic agent to inhibit SARS-CoV-2 infectivity (ability to infect) as well as that of the potentially mutated species.
Research has been done by the scientists of the University of California to discover a therapeutic agent.
Led by nanoengineering professor Liangfang Zhang at the Jacobs School of Engineering in University of California, the research is based on a new technique of forming a drug which focuses on the affected host cells instead of targeting the causative agent.
The research, published in the journal Nano Letters on 17 June 2020, is based on the fact that since SARS-CoV-2 binds with protein receptors to enter human cells, so to counteract that the scientists created cellular nanosponges which restricted their binding and neutralised them.
Nanosponges are human-made cellular substances which naturally target the SARS-CoV-2 virus. In order to form these cellular nanosponges and macrophages (infection eating white blood cells), the scientists used the outer covering (cell membranes) of epithelial cells present in the human lung. This membrane was coated onto polymeric nanoparticle cores. These polymeric nanoparticle cores were made by using ultrasound waves (sonication) on the poly lactic-co-glycolic acid (PLGA).
This whole process led to the formation of human lung epithelial type II cell nanosponge (denoted “Epithelial-NS”) and human macrophage nanosponge (denoted “MΦ-NS”).
The cell membrane coating helped these nanosponges obtain the viral receptors which are essential for the entry of the coronavirus into the host cells.
The study: Nanosponges against SARS-CoV-2 virus
The fabricated nanosponges were firstly tested in the laboratory to find out their efficacy and safety in the lungs. On testing it, the scientists found that:
- Nanosponge ‘Epithelial-NS’ had viral receptors such as ACE-2, transmembrane serine protease 2, and dipeptidyl peptidase IV
- Nanosponge ‘MΦ-NS’ had viral receptors ACE-2, C-type lectin domain family 10 (CLEC10), and CD147
The scientists then introduced these nanosponges in the trachea of mice as this novel coronavirus is mostly known to affect the respiratory tract. The scientists used the highest feasible dose of Epithelial-NS or MΦ-NS which was 300 μg (microgram) in a suspension of 20 μL (microlitre).
After three days, it was revealed that there was no evidence of lesion formation or tissue damage in the mice. Furthermore, all the blood markers, including the red blood cells, platelets, and white blood cell counts, were within the normal limits. This confirmed the short term efficacy of the nanosponges.
Results of the study
The study showed that both Epithelial-NS and MΦ-NS showed the ability to neutralise SARS-CoV-2 in a dose-dependent manner.
The laboratory tests showed that this Epithelial-NS was able to reduce the ability of SARS-CoV-2 virus to infect the host cells by 93 percent.
Whereas MΦ-NS was able to reduce the capability of SARS-CoV-2 virus to infect the host cells by 88 percent.
Conclusion of the study
Nanosponges are tiny biodegradable polymers which are covered with either cell membranes or some other coverings that mimic human cells. This attracts the virus towards them and prevents the virus from connecting with the healthy human cell. Thus, the virus gets neutralised and does not multiply in the body, as it needs human cell DNA for multiplication.
The efficiency of these cellular nanosponges for the treatment of SARS-CoV-2 infection requires further investigation on proper animal models, which is underway, followed by human clinical trials.
For more information, read our article on 4 inventive solutions to treat symptoms of COVID-19 .
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