Digital Angel Developing an Implantable Glucose-Sensing RFID Tag

By Beth Bacheldor

Oct. 31, 2006—Digital Angel Corp., a St. Paul, Minn., maker of RFID tags for identifying and tracking animals and other assets, has begun developing an RFID-enabled sensor tag it hopes will make it easier for diabetics to monitor their blood-sugar levels.

The glass-encased tag, about the size of a grain of rice and implanted via a syringe into a person's forearm, will be similar to RFID microchips implanted in animals and humans today, according to Kevin McGrath, president and CEO of Digital Angel, a subsidiary of Applied Digital Inc.. Attached to the tag, protruding from the glass encasement and exposed to human tissue, will be metallic filaments that leverage glucose-sensing technology. McGrath says these filaments have been available for some time, acting as transducers that measure and translate electrical conductivity into glucose levels.

Kevin McGrath, Digital Angel

What's been missing has been a way for the measurements captured by the filaments to communicate their findings—this is where RFID comes in. When an RFID interrogator scans the microchip—it must be 6 inches or closer to get a read—the RF signal from the reader energizes the RFID chip, providing the electric current the filaments need to measure the glucose level. The filaments take a reading and share it with the RFID microchip, which transmits the data to the interrogator.

"There are 10 million to 13 million people [in the United States] who take blood-sugar readings by pricking themselves multiple times every day," says McGrath. If you could pass a scanner over skin and take a reading in a way that doesn't hurt and is convenient—you could easily do it sitting at your desk—the people that currently measure their glucose would be much better off, and the many who aren't doing it but should, probably would."

Last week, Digital Angel was awarded a patent for its design of the glucose-sensing RFID microchip. McGrath said this step was necessary before development could get underway. "There is a lot of money associated with developing these microchips," he says. "We'll probably spend $1 million to $2 million to develop it, so we decided to get the patent first. We didn't want to spend all that time and money, and then find out it wasn't patentable." The patent, No. 7,125,382, was granted on Oct. 24 and is titled "Embedded Bio-Sensor System."