APR 16, 2016 6:49 AM PDT

Forever Body Art: The Science Behind Tattoo

WRITTEN BY: Xuan Pham

Humans have been decorating their bodies with tattoos and piercings since at least the Neolithic era thousands of years ago. While modern technologies have expanded the range of available dyes, today's technique of tattooing remains arguably similar to the technique used long ago. That is, needles insert ink deep into the dermis layer of the skin so that it becomes permanent. But skin cells shed every two to three weeks, so why doesn't the ink get sloughed off along with the cells?

The answer has a lot to do with the immune system. In fact, tattoos can be thought of as an inflammatory process. Each time a needle punctures the dermis and delivers an ink load, the body sends macrophages to the wound site to "eat" the foreign pigment particles in an attempt to clean the wound. But the dermis layer ends up trapping the stained macrophages, giving the desired permanence effect.

While permanent, the ink can fade, blur, and even migrate with aging. And reversing a tattoo's effects is similarly painful as getting it in the first place. To erase a tattoo, lasers are used to break up the pigment particles until it's small enough to be cleared out by the immune cells. This process is lengthy as it is painful and could cause scarring, which could be considered another form of a permanent tattoo.
About the Author
I am a human geneticist, passionate about telling stories to make science more engaging and approachable. Find more of my writing at the Hopkins BioMedical Odyssey blog and at TheGeneTwist.com.
You May Also Like
NOV 24, 2020
Chemistry & Physics
Want to Keep Calm? Tap Water Might Help
NOV 24, 2020
Want to Keep Calm? Tap Water Might Help
The ongoing worldwide pandemic places the mental health of many communities on red alert. But there may be a remedy to e ...
JAN 17, 2021
Space & Astronomy
Astronomers Discover Planet with 3 Suns
JAN 17, 2021
Astronomers Discover Planet with 3 Suns
Having just one star in our solar system makes us an outlier in our galaxy. However, while most solar systems in the Mil ...
APR 21, 2021
Space & Astronomy
Earth-like Planet Discovered Orbiting Red Dwarf Star
APR 21, 2021
Earth-like Planet Discovered Orbiting Red Dwarf Star
Researchers from Spain have discovered an Earth-like planet orbiting the star, GJ-740, a red dwarf star located 36 light ...
MAY 02, 2021
Space & Astronomy
Average Day on Venus Lasts 243 Earth Days
MAY 02, 2021
Average Day on Venus Lasts 243 Earth Days
Although Venus is our planet’s closest neighbour, its fundamental properties have remained largely unknown. Now th ...
JUN 21, 2021
Space & Astronomy
Scientists Detect Signatures of Life on Earth Remotely
JUN 21, 2021
Scientists Detect Signatures of Life on Earth Remotely
An international team led by researchers from the University of Bern in Switzerland and the National Centre of Competenc ...
JUN 24, 2021
Space & Astronomy
European Space Agency to Launch Satellite Made from Plywood
JUN 24, 2021
European Space Agency to Launch Satellite Made from Plywood
Modern spacecraft are typically made out of carbon fiber composites. Now, however, the European Space Agency has announc ...
Loading Comments...