Nano and Covid-19 Vaccines
The world of immunology has made use of nanotechnology for a long time. When addressing viruses such as the coronavirus that causes Covid-19, nano is a logical place to turn, because viruses themselves are naturally occurring nanoparticles. In fact, nanomedicine has for some time tried to replicate the characteristics of viruses for applications such as targeted drug delivery. But 2020 has brought vaccine development and nano to the forefront.
Nano and mRNA Vaccines
In 2020 much attention and work has been focused on coming up with a vaccine for Covid-19. Though other vaccine options are being explored, mRNA is the basis for the first two Covid-10 vaccines to be developed by Pfizer and Moderna, and issued an Emergency Use Authorization by the FDA. So how do these vaccines make use of nanotechnology?
RNA is a nanoparticle and mRNA (messenger RNA) is the genetic messenger used to convert DNA code into proteins. By encoding a protein based on the coronavirus cell, vaccine developers have found a way to get the body’s cells to reproduce that protein. This method instructs the body on how to produce antigens to stimulate the immune system and fight the virus.
Nanomedicine is also vital for delivering vaccines based on mRNA. Lipid or polymeric nanoparticles deliver mRNA to cells avoiding interfering enzymes, and thereby kickstarting the immune system.
According to an article in STAT, “Lipid nanoparticles are the fatty molecular envelopes that help strands of mRNA…avoid the body’s biological gatekeepers and reach their target cells without being degraded.” (How Nanotechnology Helps mRNA Covid-19 Vaccines Work by Elizabeth Cooney, STAT, December 2020).
An RNA vaccine contains some genetic material within a lipid. When this genetic material arrives in a cell, ribosomes react to mRNA instructions which causes the cell to replicate the spike protein on the surface of the coronavirus cell. After these newly created proteins leave the cell, antigens encounter them, and the immune system is thereby trained to recognize the virus. The immune system can then release cells that can eliminate those cells infected by the virus.
Nano and Other Types of Vaccines
There are several types of nanotechnology platform vaccines being developed to combat Covid-19 that could offer solutions to some limitations of mRNA vaccines, such as the need for cold storage.
Inovio Pharmaceuticals has developed a DNA vaccine. DNA vaccines use DNA molecules that are manipulated to target nuclear machinery in a cell and train the cell to produce the spike protein of a coronavirus. DNA vaccines are very stable but are less susceptible to fine modifications than mRNA vaccines.
Novavax and Johnson & Johnson are two companies pursuing subunit vaccines because these types of vaccines are more easily produced and scalable. These are simple vaccines that can be created and manufactured quickly. These VLPs (virus like particles) appear to mimic the molecules of pathogens and alert the immune system to them. They contain no genetic material, unlike mRNA vaccines.
Nano and Delivery of Vaccines
Nanotechnology is also being used to develop vaccine delivery systems such as self-administered microneedle patches. Another method under development is single-dose implants that slowly release antigens. Though still in early stages, these delivery methods may be especially useful in poorer nations or areas that lack medical personal to administer vaccines.
The world is anxiously awaiting relief for the global pandemic that has infected and killed millions. In the race to produce effective vaccines for Covid-19, several companies and universities are pursuing different options, but in all cases, nanotechnology is a key element that could lead to success.