technology today
Alan Pierce pierceaj@techtoday.us
Fake Tattoo Can Monitor a Person’s Vital Signs
Fake tattoos are about to go from being a novelty item and fashion statement to being a medical diag- nostic tool. Professor John Rogers and his team at the University of Illinois have developed a prototype temporary tattoo that contains epi- dermal microelectronic circuits on a clear rubber transfer medium.
The team’s temporary body art tattoos have a medical function. They are designed to monitor peo- ple’s vital signs while they are up and about performing their normal daily activities. His prototype showed proof of concept as it measured body temperature, electrical signals from nearby muscles and organs, and also registered physical strain in the area where they were attached to the body.
The pirate tattoo in Photo 1 re- cords the electrical activity of mus-
Photo 1
cles and nerves when it is attached to a person’s wrist. It is a micro- sized, camouflaged EMG (electromy- ography) machine. The tattoo layer
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just under the image of the pirate contains the epidermal electronics that pick up the body’s electrical signals (Photo 2).
With further development, the team hopes to go from proof of con- cept to tattoos that can transmit the signals that they pick up from the body to a separate recording device that would be about the size of a small cellphone. Wireless commu- nication is not yet possible, Rogers wrote in an email, adding, “we have shown functionality in the building block components for such systems (wireless transfer of information), but we do not yet have that capa- bility in our tattoos. For now, as a temporary strategy to demonstrate functionality in the sensing part, we
Photo 2
are using ultra-thin ribbon cables as a hard-wired connection.”
These tattoos can record other vital signs when attached to appro- priate skin locations. If located on the chest, a tatoo can pick up and transmit the electrical signals from a person’s heart, thereby performing an EKG (electrocardiogram) diag- nostic test. If attached to a person’s forehead it can record brain activity and gather the same electrical sig- nals from the brain as those gathered by an EEG (electroencephalogram) machine. (To perform a true EEG test, they would have to be applied to numerous locations on a person’s head.)
Alan Pierce, Ed.D., CSIT, is a tech- nology education consultant. Visit www.technologytoday.us for past columns and teacher resources.
| The electronics in these tattoos | from the human body to a computer | id=70971&org=NSF. You can also |
| are extremely thin and flexible. They | could lead to nonmedical uses. In | view videos by John Rogers and |
| are embedded in a transparent rub- | one demonstration, Rogers showed | his team at http://news.illinois. |
| ber transfer film that is made rigid by | that the electrical signals gathered | edu/news/11/0811skin_electronics_ |
| a paper backing until it is transferred | from a person’s neck muscles could | JohnRogers.html. |
| be used to control a video game. | Recalling the Facts | |
| Tests performed to date definitely | ||
| raise the possibility that this tattoo- | 1. What is the most significant dif- | |
| computer interface could be used to | ference between this tattoo vital sign | |
| control artificial limbs. | monitoring system and our current | |
| You can view a National Science | medical monitoring systems? | |
| Foundation video on this technology | 2. How might this technology | |
| online at www.nsf.gov/news/news_ | eventually help people with different | |
| videos.jsp?cntn_id=121343&media_ | handicapping conditions? |
Photo 3
to a person’s skin. The transfer process is very similar to the one children use to transfer fake tattoos. In this case, you place the transfer against the skin, rubber side down, and then use water to dissolve its paper backing.
The tattoos can bend and stretch without breaking or degrading their ability to gather electrical signals from the body. They are so strong and flexible that they can actually be poked without breaking. Photo
3 shows the tattoo’s electronics without the overlay of a camouflage layer so you can see just how much poking the device can take without breaking.
Since the electronic circuits used in the tattoos are so tiny, they are also very energy efficient. The goal is for each tattoo to have photocells onboard to generate the electricity they will need to function. To ad- dress situations in which light isn’t an available power source, the goal is to recharge the tiny internal power supply by electrical induction. Rog- ers’s team has already tested a tiny coil onboard the tattoo to see if electric current can pass wirelessly between the tattoo and a power source.
There is no doubt that it is going to take time for this technology to move from the laboratory to a doc- tor’s office. The fact that these tat- toos can transmit electrical signals
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