Tech Briefs Magazine - April 2024 - 36

5 mm
A microneedle patch tattoo is pressed to the skin. (Image: Georgia Tech)
Tattoos are used in medicine to cover
up scars, guide repeated cancer radiation
treatments, or restore nipples after
breast surgery. Tattoos also can be used
instead of bracelets as medical alerts to
communicate serious medical conditions
such as diabetes, epilepsy, or allergies.
Various cosmetic products using microneedles
are already on the market -
mostly for anti-aging - but developing
microneedle technology for tattoos is
new. Prausnitz, a veteran in this area, has
studied microneedle patches for years to
painlessly administer drugs and vaccines
to the skin without the need for hypodermic
needles.
" We saw this as an opportunity to leverage
our work on microneedle technology
to make tattoos more accessible, " Prausnitz
said. " While some people are willing
to accept the pain and time required for
a tattoo, we thought others might prefer a
tattoo that is simply pressed onto the skin
and does not hurt. "
Tattoos typically use large needles to
puncture repeatedly into the skin to
get a good image, a time-consuming
and painful process. The Georgia Tech
team has developed microneedles that
are smaller than a grain of sand and are
made of tattoo ink encased in a dissolvable
matrix.
" Because the microneedles are made
of tattoo ink, they deposit the ink in the
skin very efficiently, " said Li, the lead
author of the study. In this way, the microneedles
can be pressed into the skin
just once and then dissolve, leaving the
36
ink in the skin after a few minutes without
bleeding.
Although most microneedle patches
for pharmaceuticals or cosmetics have
dozens or hundreds of microneedles arranged
in a square or circle, microneedle
patch tattoos imprint a design that
can include letters, numbers, symbols,
and images. By arranging the microneedles
in a specific pattern, each microneedle
acts like a pixel to create a tattoo image
in any shape or pattern.
The researchers start with a mold
containing microneedles in a pattern
that forms an image. They fill the microneedles
in the mold with tattoo ink
and add a patch backing for convenient
handling. The resulting patch is then
applied to the skin for a few minutes,
during which time the microneedles
dissolve and release the tattoo ink. Tattoo
inks of various colors can be incorporated
into the microneedles, including
black-light ink that can only be seen
when illuminated with ultraviolet light.
Prausnitz's lab has been researching
microneedles for vaccine delivery for
years and realized they could be equally
applicable to tattoos. With support
from the Alliance for Contraception in
Cats and Dogs, Prausnitz's team started
working on tattoos to identify spayed
and neutered pets, but then realized
the technology could be effective for
people, too.
The tattoos were also designed with
privacy in mind. The researchers even
created patches sensitive to environwww.techbriefs.com
Medical
alert tattoo: microneedle patch (above)
and tattoo on skin (below). (Image: Song Li,
Georgia Tech)
mental factors such as light or temperature
changes, where the tattoo will only
appear with ultraviolet light or higher
temperatures. This provides patients
with privacy, revealing the tattoo only
when desired.
The study showed that the tattoos
could last for at least a year and are
likely to be permanent, which also
makes them viable cosmetic options
for people who want an aesthetic tattoo
without risk of infection or the
pain associated with traditional tattoos.
Microneedle tattoos could alternatively
be loaded with temporary tattoo ink
to address short-term needs in medicine
and cosmetics.
Microneedle patch tattoos can also be
used to encode information in the skin
of animals. Rather than clipping the ear
or applying an ear tag to animals to indicate
sterilization status, a painless and
discreet tattoo can be applied instead.
" The goal isn't to replace all tattoos,
which are often works of beauty created
by tattoo artists, " Prausnitz said.
" Our goal is to create new opportunities
for patients, pets, and people who
want a painless tattoo that can be easily
administered. "
For more information, contact
Georgia Parmelee at georgia.parmelee@
gatech.edu.
Tech Briefs, April 2024
http://www.techbriefs.com
Tech Briefs Magazine - April 2024

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