Histology of TattoosChandler Hicks, Stefanie Schutz, Paula Bang

Trinity University Department of Biology

History A tattoo is a permanent mark or design made on the skin by a process of pricking and ingraining an indelible pigment or by raising scars. The art of tattooing has been around as early as the stone age (12,000 BC), and was used by the ancient Egyptians, Romans, and Asian cultures. Stone age tattoo application consisted of using sharpened bone needles and red ochre for ink, while the traditional Japanese method consisted of a group of needles attached to a stick of bamboo. The modern tattoo gun was created in 1891 by Samuel O’Reilly and has evolved into various forms. Although the method of tattoo application has varied amongst cultures, the use of tattoos have not. Tattoos are used for individuality, sexuality, cosmetic, and medical purposes. Approximately 14% of Americans have tattoos.

Figure 1. Polynesian tattooing tools. [1]

The process of receiving a tattoo is invasive but it’s invasiveness that results in permanency. The 3-18 needles of a tattoo gun deposit drops of ink into the papillary layer of the dermis. The needles cause damage to the epidermis and, in turn, an inflammatory response. The inflammatory response causes the redness you see around a fresh tattoo.

UV Tattoos

The application of UV tattoos is the same as regular ink tattoos. The difference between the two inks resides in the type of ink particle. UV tattoo ink can made many different ways. However, they all share the presence of unstable phosphorescent elements, which store energy and appear to glow under the right conditions. UV tattoo inks have a polymer microsphere (Polymethylmethylacrylate or PMMA) that standard inks do not. The microscopic bead encases the dye molecules. PMMA microspheres are 4-5 times larger than red blood cells and are typically well tolerated by the skin tissue. Unlike standard tattoos, the microsphere prevents the dye color from ever coming in contact with the person. The ink-filled shells sit between the skin cells with biocompatibility. The PMMA shell can only be broken down if frozen solid.

Acknowledgements

HealingThe area fills with neutrophils and macrophages, which try to phagocytize the ink granules and present them as antigens, but the size, and makeup of the granules prevent this action. The ink granules remain in the papillary level of the dermis and are eventually engulfed by fibroblasts and fixed macrophages, which work to repair the damage from the needles by creating scar tissue. Once the scar is formed, the ink is permanently held in the dermis.

Aging

Application As tattoos age, they can take on a fuzzy or faded appearance. This is result of two things: ink sinking deeper into the dermis, and macrophages and other cells removing the granules, and presenting them as antigens in the lymph nodes. As ink is both moved and removed, more scar tissue is formed in its place, and the remaining ink becomes less visible.

Figure 2. Modern tattoo gun. [2]

Figure 9. Size comparison of UV ink particle to red blood cell. [3]

Figure 10. Image of UV tattoo.[4]

1. http://www.britishinkdc.com/paul_tattooing_methods.html2. http://www.wtfaccessories.com/blog/tag/tattoo-guns/3. http://captainjackstattoo.com/content/blacklight-inks4. http://www.tattooartists.org/

Gal15405_Blake_s_Halloween_UV_Tattoo._More_photos_in_Gallery..asp5. http://emedicine.medscape.com/article/1121212-overview#a16. http://www.statisticbrain.com/tattoo-statistics/7. http://iheartautopsy.com/?paged=98. http://medcell.med.yale.edu/histology/skin_lab.php9. http://www.anatomybox.com/tattoo/10. http://izifunny.com/2012/11/08/unlucky-choice-scarlett-johanssons-new-tattoo-2-pics.html11. http://www.thenakedscientists.com/HTML/questions/qotw/question/237212. http://archives.evergreen.edu/webpages/curricular/1998-1999/humanbio/TattooInk.htm13. http://www.shoulditattoo.com/wp-content/uploads/2011/09/P20.jpg Special thanks to Trinity University and Dr. Blystone Figure 3. Fresh Tattoo with redness. [10] Figure 4. Needle depositing ink into dermis.[13]

Figure 5. Ink in the papillary layer of the dermis.[8] Figure 6. Ink within scar tissue.[11]

Figure 7. Aged and faded tattoo on knee.[6] Figure 8. Ink in they lymph node. [7]