While it's important to have ID cards for your dogs and cats in case they get lost, tags can come off and microchips can become dislodged, so Japanese scientists are developing an alternative in the form of a quick and painless tattoo. Yes, some pet owners do have their animals tattooed. However, because the tattooing process is time-consuming, traumatic, and somewhat painful, the animal is usually given a general anesthetic beforehand.
In search of an easier way to tattoo pets, researchers at the University of Tokyo recently turned to so-called microneedle patches.
In most cases, these devices take the form of a small, flat piece of material with a series of tiny, sharp, drug-filled nails -- or "microneedles" -- at the base. The main patch is typically made from a nontoxic polymer, while the needle is made from a substance that harmlessly dissolves once it enters the body.
When the patch is placed on a patient's skin, the microneedles penetrate the outer layer of skin but do not touch any nerves underneath. The needles dissolve quickly, releasing the drug or ink into the interstitial fluid between skin cells.
In the patch system, scientists at the University of Tokyo used microneedles (less than 1 mm in length) made of hyaluronic acid, which occurs naturally in the human body. These needles are filled with non-toxic black tattoo ink molecules. Additionally, the needles are arranged on each patch in such a way that they form a dotted image of a specific letter or number.
In tests on rats, the microneedle patch was successfully used to tattoo these alphanumeric characters on bare skin. A month later, the characters were still clearly visible to the naked eye.
More research needs to be done next, including long-term durability testing. It is hoped that this technology will eventually be used not only for pets, but also as a means of identifying livestock and tracking wildlife.
A paper on the research, led by Jongho Park, was recently published in the journal Scientific Reports.
If you're thinking, "Well, can microneedle patches be used to tattoo humans?" Georgia Tech scientists are already looking into that question.