Tattoos are a self-expressing medium present since the Bronze Age – religious, cultural, sentimental and mystical meaning is attached to this ancient practice. Archaeologists have found evidence that tattoos were also used for medical purposes.
In the past
Tattoos on the wrists, knees and lumbar part of the spine have been observed on human remains dating back to 3300 BC. Radiographic analysis revealed clinical evidence of osteochondrosis (non-inflammatory, non-infectious disorders of bone growth in various ossification centers, which occur at the time of their greatest developmental activity, and affect the epiphyses) in these joints. Furthermore, tattoos were found in the pelvic area on Egyptian female mummies. Medical historians believe that chronic pelvic peritonitis (infection of the upper female reproductive system: cervix, uterine body, fallopian tubes and ovaries) was treated in this way. Due to the above findings, medical and acupuncture experts conclude that these tattoos were a form of treatment.
Today, tattoos are used for medical purposes to cover the scars of burn victims with hyperpigmentation of the skin, vitiligo and related conditions. Tattoos are also used to indicate to medical staff the existence of allergies and certain diseases such as asthma, diabetes, epilepsy and cystic fibrosis. In oncology, tattoos are used in breast reconstruction after mastectomy, three-dimensional reconstruction of the areola gives the impression of a realistic nipple. Medical tattoos are a replacement for medical alert bracelets that can be lost or broken.
In the future
In The DermalAbyss project, researchers replaced traditional tattoo ink with colorimetric and fluorescent biosensors that detect changes in glucose, sodium and pH levels in the interstitial fluid of the skin. A change in the concentration of any of these parameters was accompanied by a change in the color of the tattoo, and the intensity of the color correlates to the concentration of the analyte. For example, a change in pH from 7.0 to 7.4 is accompanied by a change in color from pink to blue. Such tattoos would be a useful tool in continuously monitoring the health of patients. In particular, these biosensors would be useful for monitoring diabetes, dehydration and conditions that lead to pH imbalance. All biosensors can be incorporated into the same tattoo on the patient’s wrist. The color change on the tattoo is monitored by a smartwatch with a camera. The watch emits light with a wavelength of 507 nm, which causes the tattoo to reflect back the tattooed word “ON” in fluorescent green at a wavelength of 532 nm, which indicates the sodium level. A flash of light on the wavelength 530 nm enables the watch to interpret the spectrum. The watch stores this information, which can be shown to the doctor at the next appointment.
Biosensor ink could find its use in diagnostics in the form of temporary tattoos. The skin is a protective barrier and as such is rich in immune cells. Since tattooing elicits a stronger immune response than the intramuscular injection used for vaccination there is an idea to get vaccinated by tattooing. A UV-sensitive tattoo ink is also being developed, the color change of the tattoo would signal that it is time to take sun protective measures.
Translated by Patricia Štriga
2. Pazos MD et al. Tattoo Inks for Optical Biosensing in Interstitial Fluid. Adv Healthc Mater. 2021 Nov; 10(21): e2101238.
3. Vega K et al. The Dermal Abyss: Interfacing with the Skin by Tattooing Biosensors. ISWC ’17: Proceedings of the 2017 ACM International Symposium on Wearable Computers. 2017: 138 – 145.