December 5, 2007

Tattoos Could Replace Needle Sticks For Diabetics

A diabetes "tattoo" might be just the thing to relieve diabetes
sufferers of the constant pain of needle sticks. Most
glucose-monitoring methods require that a blood sample be taken using a
needle; researchers have long sought a non-invasive test method.
Finding a less painful way of monitoring blood sugar could make a real
difference to the 6.7 percent of Americans who have diabetes.

Gerard Cote, biomedical engineering professor in the Dwight Look
College of Engineering, is testing an experimental system using fluorescent polymer microbeads
implanted just under a patient's skin. Glucose levels affect how much
light the beads emit when exposed to laser light; the blood glucose
level could be measured with a wristwatch-like monitor.

When injected under the skin, the microbeads cannot enter
cells - unlike tattooing, in which cells absorb the pigment. The beads
remain in the spaces between the cells; these interstitial spaces are
filled with water and glucose molecules. According to Dr. Cote, the
level of glucose in interstitial fluid is directly related to the blood
glucose level measured by the traditional needle-stick method.

The glucose in the fluid binds to the microbeads; when the beads
are illuminated with a small laser, the fluorescent color of the beads
changes in proportion to the amount of glucose present.

In preliminary studies, the researchers injected the microbeads
under the skin of a laboratory rat, and found that the rat tolerated
the implant. The beads did in fact fluoresce under the rat's skin; the
fluorescent response changed when there was a change in glucose level
in the rat.

Active tattoos can be found in various science-fictional works;
consider the subdermal microchannels from the 1985 cyberpunk classic Stone Lives by Paul Di Filippo:

June's body is a tracery of lambent lines, like some arcane capillary
circuitry in the core of Mao/K'ung Fu-Tzu. Following the current craze,
she has had a subdermal pattern of micro-channels implanted. The
channels are filled with synthetic luciferase, the biochemical
responsible for the glow of fireflies.

(Read more about Di Filippo's Subdermal Microchannels)

A similar idea is used in the novel Nova Swing by M. John Harrison.

Don't miss these unusual tattoo stories:

Via Texas A&M Engineering: Fighting diabetes where It hurts. Thanks to reader KafirCake for the tip on the story.

(This Science Fiction in the News story used with permission of - where science meets fiction