Engineers at the University of California San Diego developed and tested "nanosponges" covered in human lung and immune cell membranes that attract and neutralize SARS-CoV-2. They published their research on June 17 in the journal Nano Letters.
This new technology can soak up harmful pathogens and toxins, hence the name "nanosponges."
During the lab experiments, both lung and immune cell types of the nanosponges reduced the viral infectivity of SARS-CoV-2 to nearly 90% in a dose-dependent manner. Viral infectivity means that it is a measure of the virus's ability to infect the host cell and exploit its resources to replicate and create additional infectious viral particles.
How Does It Work?
These nanosponges do not target the virus since they are designed to protect healthy cells that the virus invades.
Liangfang Zhang, a nanoengineering professor at the UC San Diego Jacobs School of Engineering, first created this biomimetic nanosponge platform more than ten years ago and has since developed a variety of applications ever since.
When the coronavirus emerged, Zhang thought "almost immediately" that his idea of using the nanosponge platform to fight the novel coronavirus will be helpful.
Since the nanosponges are covered with membranes that mimic human cells, the virus will be interested in binding with their surface instead of the virus infecting cells in the body, which could multiply and spread the infection.
The virus is tricked into infecting the nanosponges, which do not have the capacity to multiply, reducing the viral load and hence the opportunity to spread the infection, Forbes reported.
Zhang designed two types of nanosponges using membranes from human lung cells, macrophages, or specialized white blood cells. Each of these types is coated with ACE2 and CD147 receptors and infected by the SARS-CoV-2, the virus that causes COVID-19.
Aside from the encouraging data on neutralizing the virus, the researchers also note that nanosponges could soak up inflammatory cytokine proteins, which are implicated in some of the most dangerous aspects of COVID-19 and are driven by the immune response to the infection.
Zhang expects the nanosponges to work against any virus, especially to a new virus, which may become the source of another pandemic. He predicts that a typical treatment might involve infusion of "trillions of sponges," but animal and human trials must first be conducted to determine the right dosage.
Applications of Nanosponges
The first nanosponges that Zhang and his team developed were designed to treat bacterial pneumonia. Presently, Cellics Therapeutics in San Diego have completed conducting the pre-clinical testing. They are now in the process of submitting an investigational new drug (IND) application to get approval from the FDA to use the red blood cell nanosponges to treat patients with methicillin-resistant staphylococcus aureus pneumonia.
Moreover, Zhang's team at UC San Diego have also demonstrated that nanosponges can deliver a drug to the wound site, bind bacterial toxins, and bind HIV viral particle before it can infect human T cells.
Zhang explains that the nanosponge's construction is predicated on a similar basic principle wherein a biodegradable, FDA-approved polymer core coated in a specific type of human cell membrane prevents the immune system from recognizing and attacking the particles as dangerous invaders.
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