Scientists from the Massachusetts Institute of Technology (MIT) have developed a stick-on-tattoo for powerful delivery of vaccines.
The tattoo is a patch covered in 'micro-needles' and may be a far safer, and less painful, way to deliver a new generation of vaccines, 'Daily Mail' reported.
Researchers claim the system could even be used to deliver DNA vaccines for 'risky' diseases such as HIV.
Applying patches loaded with these needles onto the skin instantly embeds the coatings into the body, much like the application of a tattoo.
These micro-needles can be designed to disrupt only the most superficial layers of the skin to avoid nerve endings and blood vessels, making them painless and safer than hypodermic needles.
However, researchers have struggled to find a way to deliver them effectively - with the best methods so far involving injections and the applying an electrical current to the skin.
Scientists tested the patches on rhesus monkeys, measuring how much of a protein encoded by a DNA vaccine the animals would produce.
The monkeys generated 140 times as much of the protein in response to micro-needles as they did when injected using normal, hypodermic needles.
"Comparing it to feeling like a cat's tongue is quite accurate,' researcher Peter DeMuth, a biological engineer and materials scientist at MIT, told TechNewsDaily.
"We have very direct control over how the vaccine is delivered, and the prolonged exposure to the vaccine that is possible with this system can really enhance immunity," said DeMuth.
The new 'tattoo' is made of creating a patch made of many layers of polymers embedded with the DNA vaccine.
These polymer films are implanted under the skin using micro-needles that penetrate about half a millimetre into the skin - deep enough to deliver the DNA to immune cells in the epidermis, but not deep enough to cause pain in the nerve endings of the dermis.
Once under the skin, the films degrade as they come in contact with water, releasing the vaccine over days or weeks.
