Vaccines typically involve injecting inactivated viruses into your body; the immune system remembers these invaders so it can mount a defense if it encounters the real thing later on. This approach, however, can be too risky with certain viruses, such as HIV.
Specifically, it’s DNA coding for viral proteins: this DNA snippet encodes for a specific antigen (something that causes an immune response). Once it’s in an immune cell, it gets the cell to produce more of the antigen.
So far, no company has successfully developed a DNA vaccine. But if such vaccines could be successfully delivered to humans, they would overcome the safety risks of vaccinating against many diseases. They’d also be more stable, making it possible to ship and store them at room temperature; and they’d eliminate the need to inject vaccines by syringe, making it pain-free.
According to MIT’s Darrell Irvine, you just apply a patch for a few minutes, take it off, and the thin polymer film left behind becomes embedded in the skin. They call it a ‘multilayer tattoo.’
- They created a patch made of many layers of polymers embedded with the DNA vaccine.
- These polymer films are implanted under the skin using a bed of microneedles that painlessly penetrate about half a millimeter deep.
- Once under the skin, the films degrade as they come in contact with water, releasing the vaccine over days or weeks.
- As the film breaks apart, the DNA strands become tangled up with pieces of the polymer, which protect the DNA, helping it get inside cells.
- Since the DNA is released over time, it interacts with the immune system for longer, boosting the vaccine’s effectiveness.
The team will test more in non-human primates before moving on to humans. Previous DNA vaccination attempts include injecting DNA under the skin and then using electrodes to open small pores in the cells. (Painful.)
The work was published in Nature Materials last month.
[Via MIT News Office]
Image from P.C. DeMuth et al., Nature Materials