Hacking the Human Body With Temporary Tattoos and Tiny Implants

Using electrical charges to treat diseases, from diabetes to obesity, is picking up speed

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This temporary tattoo could save diabetics from the daily annoyance of pin pricks to their fingers. Jacobs School of Engineering/UC San Diego

When devices can track every step we take and body parts are being made on 3-D printers, it seems oddly primitive that people with diabetes still have to poke their fingers every day to check the level of their blood sugar. It’s not surprising that’s one of the big reasons many diabetes patients fall off the track when it comes to managing their conditions—they get tired of all the pin pricks.

But relief from sore finger tips appears to be on the way, in the form of a simple pleasure of childhood—the temporary tattoo. A research team at the University of California, San Diego has created a flexible sensor printed on thin tattoo paper that sticks to a person’s skin. Once attached, the strip’s electrodes generate a mild current for about 10 minutes after each meal. That current draws glucose, carried through the body by positively-charged sodium ions, closer to the surface of the skin. By measuring how strong the charge is just under the skin, the sensor estimates how much glucose—the sugar that diabetics have trouble breaking down—is in the bloodstream.

A device called the GlucoWatch, approved by the FDA in 2001, operated by the same general principle, but it never caught on. The problem was that it caused skin irritations and often told people their blood sugar levels were higher than they actually were.

So far, the temporary tattoo has avoided those problems, in part because it uses a lower electrical current. Seven people between the ages of 20 and 40, who participated in a test, reported nothing more than a slight tingling when the tattoo was taking measurements. And those measurements, gathered after carb-rich meals of sodas and sandwiches, were very similar to blood sugar readings taken through traditional finger sticks.

Each tattoo lasts a day, before needing to be replaced. That may sound pretty inefficient, but the blood sugar sensor strips are inexpensive—only a few cents each, according to lead researcher Amay Bandodkar.

In its experimental stage, the temporary tattoo can’t provide the person wearing it with a numerical value of their blood sugar level. But the goal is to give the tattoo Bluetooth capabilities that will allow it to send the data directly to a mobile device or a doctor’s office.

The diabetes temporary tattoos will not be at your neighborhood drugstore any time soon. The San Diego research was done to create a proof of concept. Would the approach work, and how well? But based on the results, Bandodkar feels temporary tattoos could also be used to measure other compounds in the blood, such as medications or levels of alcohol.  

The body electric

The idea of using electric impulses to manipulate or treat ailments is hardly new—the first pacemaker was implanted into a human body in 1958. But until very recently, the devices usually were clunky and not particularly precise, often stimulating more neural circuits than they needed to.

Now, however, a new field of medical research, sometimes referred to as “electroceuticals,” is taking shape. It involves the use of implantable electronic devices to control the body’s neural circuits—and operates according to the theory that if you can map the neural pathway of a disease, you could then use tiny electrodes to treat it. By focusing on particular neurons, treatments could be far more precise than flooding a whole system with drugs. 

GlaxoSmithKline, the British pharmaceutical and healthcare company, is already betting on this kind of bioelectrical research. It has created a $50 million fund to support as many as seven device startups in the field, and last fall committed another $5 million to an Innovation Challenge Fund to encourage researchers to develop bioelectrical devices.

The National Institutes of Health has jumped in, too, announcing last fall that it will spend almost $250 million over the next six years to map the neural pathways and electrical activities of five different organ systems, and then develop devices that can attach to the appropriate nerves and fight diseases in those organs. This will be no small undertaking. Researchers will need to be able to identify which nerves do what for an organ so they know where to apply the electrical charge.  

But already, bioelectronic devices are showing where medicine is headed:

  • Earlier this month, the Food and Drug Administration (FDA) approved a device that stimulates nerves in the stomach to help obese people lose weight. The Maestro Rechargeable System consists of a small disc, implanted under the skin against the ribs, that generates an electrical pulse. That pulse sends signals that block the vagus nerve, resulting in the person feeling full.
  • Last year, the FDA gave the go-ahead to a device implanted near the collarbone that mildly shocks the hypoglossal nerve under the chin. It’s a new kind of treatment for sleep apnea, the condition in which people stop breathing during sleep because their airways temporarily close. The electric pulses are designed to keep the airways open.
  • More than half of the patients with severe rheumatoid arthritis in a recent clinical trial in Amsterdam said their pain was reduced after a device was implanted in their necks. Using a magnet, the patients were able to turn on the device for three minutes every day. The resulting electrical impulses reduced the number of immune cells traveling to their joints, easing the inflammation that causes pain.
  • Researchers in Germany were able to lower the blood pressure of rats by as much as 40 percent with a device that wraps around a nerve in the neck. The scientists said the blood pressure dropped within five seconds after the nerve was stimulated.
  • Late last year, the FDA approved the first wireless neuromodulation device that can help relieve chronic back and leg pain. The tiny implantable device, only a few centimeters in length, triggers a reaction that enables the brain to remap specific pain signals.

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