Let’s Test the Sugar in Your Sweat
A noninvasive meter that measures glucose in perspiration instead of glucose in blood is being developed.
VivoMedical, Inc., of Cupertino, California, has conducted preliminary clinical studies on humans to establish the correlation between the glucose in sweat and glucose in blood.
“The results are encouraging,” CEO Robert Blair tells me. “We are targeting the replacement of the blood-stick with a skin patch and a reader.”
VivoMedical is only two years old. But the company began in 2000 as MedOptix Inc.
“We founded MedOptix to detect glucose on the skin surface with an optical detector,” Blair says. “But we concluded that the question of its glucose specificity is a huge hurdle.”
While spectroscopy is sensitive, it’s not glucose-specific enough, Blair says. You might think that you are looking at the desired glucose signal, but it might just be an artifact, giving an erroneous reading.
I asked him how they were able to shift gears. “We were always looking at sweat on the skin surface, and that wasn’t a shift,” he says. “What has changed is the sensor technology. We concluded that we couldn’t detect glucose unambiguously with an optical sensor, but we can with a glucose-oxidize electrochemical sensor—the same chemistry that the bloodstick uses.”
The patent application describes a patch the size of a Band-Aid placed on the skin. The planned application site is the palm or a finger, because these areas have a high density of sweat glands and are convenient for the user. After testing, the patch will simply be discarded.
Blair hopes to price the VivoPatch competitively with test strips. The VivoReader should likewise be priced about the same as blood glucose meters, when produced in volume.
The old saying has it that “laborers sweat, gentlemen perspire and ladies glow.” But everybody sweats at least a little, because it is part of the body’s thermal management system, says VivoMedical’s chief scientist Russell Potts.
For decades, scientists have known there is glucose in sweat, he says. “The trick is to correlate it with blood glucose. That is pretty much what we have figured out.”
For more information, log on to www.vivomedical.com.
The Glucose Market Wheel
You can divide all of the existing and forthcoming blood glucose-monitoring systems into those that are invasive and those that are noninvasive. And then you can divide those two groups into those that use glucose-specific detector technology and those that are working with glucose nonspecific detector technology. That gives you what VivoMedical’s Robert Blair calls a “market glucose wheel.”
Blair says that all glucose monitors fall into one of these four quadrants. “As far as we can determine, VivoMedical is the only company in that sector of the glucose wheel that is both noninvasive and glucose specific,” he says. “VivoMedical therefore appears to be unique in its approach of using glucose in sweat as the surrogate for blood, together with using an approved chemistry as the sensor technology for glucose.”