Syringe, needle, iodine, cotton balls and a drop of blood: You are now entering the territory of the most dreaded of all visits to the doctor – the one where you need an injection.
Having cold, surgical steel jabbed into various parts of the body to deliver a necessary vaccination is an event that few of us enjoy.
Luckily, there are people out there who are trying to come up with a way of administering a shot that doesn’t involve pointy steel needles.
Researchers at the Massachusetts Institute of Technology (MIT) are in the process of developing a microscopic “tattoo” that can inoculate patients painlessly.
The “tattoo” is actually a tiny plastic patch, smaller than a penny, equipped with hundreds or even thousands of microneedles coated with a special vaccine.
“You can see this pattern of very small, microscopic needles on the surface of the patch. These needles are actually on the order of half a millimetre or less in length,” says MIT scientist and lead engineer for the tattoo vaccine, Peter DeMuth.
Needles this tiny are not long enough to reach sensitive nerve endings in the dermis, meaning less discomfort. DeMuth says: “Comparing it to feeling like a cat’s tongue is quite accurate.”
Since tattoos are an entirely new method of delivering vaccinations, the vaccine itself has had to be rethought.
Today, the most widely used forms of vaccines are known as first-generation vaccines. They are created from weakened or dead microbes injected into our bodies via syringe.
The presence of these invading microbes in our system creates an immune response from T-cells and antibodies, which fight the infection.
A white blood cell chases a radical bacteria in the human body.
DeMuth and his MIT research team are testing the tattoos with a third-generation or DNA vaccine.
These vaccines work by injecting a thread of weakened microbe DNA directly into your body’s cells.
A strand of DNA
An depiction of microneedles puncturing the skin's epidermis to inject the DNA vaccine.
The DNA holds a code for a protein from a virus or bacteria, foreign to your own body. This triggers your body’s immune response to the invading protein, destroying it before it takes hold.
The real advantage of the DNA tattoo vaccine is that it requires no refrigeration, meaning people living in remote areas of the world could finally have proper access to preventative medicine.
As DeMuth and his colleagues have discovered, getting the DNA vaccine to stick to the plastic microneedles requires some ingenuity.
“The way that we make the coating is that we take the components that make up our vaccine: one of the components is negatively charged and one of the components is positively charged,” says Paula Hammond, David H. Koch Professor in Engineering.
In a fondue-like process, a negatively charged tattoo is dipped into a positively charged polymer (plastic) coating followed by a dip into a negatively charged DNA coating.
This process can be repeated dozens of times, creating a thick film on each individual needle.
A robotic arm dipping the "tattoo" into the vaccine/polymer liquids
“You just apply the patch for a few minutes, take it off and it leaves behind these thin polymer films embedded in the skin,” says Darrell Irvine, MIT Professor of Biological Engineering and Materials Science and Engineering.
These films eventually dissolve and release the vaccine over the following days or weeks.
According to medscape.com, clinical trials have shown that microneedle tattoos are a promising alternative to surgical needles and some products on the market already use this technology, such as Dermaroller – a collagen stimulating tool used to repair sun-damaged or scarred skin.
A Dermaroller treatment session
The DNA vaccines that researchers like DeMuth hope will coat the tattoo’s microneedles are still in trial phase. For now, vaccinations will retain their grimace-provoking, queasiness-inducing reputation.
Children and adults alike will just have to wait that little bit longer for the next best thing since sliced bread… an ouch-free needle.
For more information about the microneedle tattoos and DNA vaccines, please visit: http://newsoffice.mit.edu/2013/vaccine-film-delivery-hiv-0127