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TRANSDERMAL CONTINUOUS GLUCOSE MONITORING: Two key components of the Symphony tCGM are the Prelude SkinPrep System that works a bit like an electric razor, using microdermabrasion to shave away the dead outermost surface of the skin in a dime-size spot on the body, and a glucose biosensor that is applied to that spot (generally on the chest or upper back).
Image: © ECHO THERAPEUTICS
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For many diabetics, the unpleasant chore of drawing blood several times a day in order to check blood glucose levels is a part of life. Efforts to develop devices that can test blood glucose without the need to repeatedly prick fingers have faltered thus far due to questions about accuracy as well as complaints about skin irritation. One company is hoping to solve these problems with a biochemical sensor that adheres to the skin like a bandage and sends continuous blood glucose readings to a handheld wireless device.
A proper blood glucose level is essential to one's health, especially for diabetics, whose bodies either produce none or too little of the glucose-regulating hormone insulin. Because high blood glucose levels can lead to a long list of serious health problems—glaucoma, nerve damage and heart disease, to name a few—diabetics must test their glucose levels several times each day, typically using a lancing device to pierce a fingertip and draw blood.
Echo Therapeutics, based in Franklin, Mass., is developing a wireless, needle-free transdermal continuous glucose monitoring system called Symphony tCGM for diabetics (there are nearly 24 million in the U.S.) and for use in hospital critical care units.
Symphony tCGM has three basic components: a Prelude SkinPrep System—a device roughly the size and shape of an electric nose-hair clipper—that shaves away the dead outermost surface of the skin (microdermabrasion), leaving a dime-size spot; a glucose biosensor that is applied there (generally on the chest or upper back); and a wireless handheld device that reads glucose levels from the biosensor.
As the Prelude removes skin and hair that could interfere with the biosensor's reading, it passes tiny electric pulses into the skin, says Echo Therapeutics chairman and CEO Patrick Mooney. Based on the response to these pulses, the Prelude can determine when it has reached live underlying skin cells that allow the biosensor to provide a more accurate reading. The patient then applies the disk-shaped biosensor to the patch of skin prepped by the Prelude. The membrane on the biosensor's surface detects glucose as it diffuses out of the body's capillaries. The sensor contains an enzyme that reacts with the glucose and relays the indication as an electric signal. The impulse passes wirelessly to a handheld device, which records the information and monitors the readings. Each sensor can be used for two days before being replaced by a fresh one, and then either used in the same spot or another Prelude-treated location.
Tufts Medical Center in Boston spent several years as a clinical site testing Echo's Symphony tCGM. "We frequently during surgery take blood samples for instantaneous testing" of blood glucose levels, regardless of whether the patient is diabetic, says Michael England, the center's chief of adult cardiac anesthesia. Continuous monitoring is particularly important during surgery because patient insulin levels vary. "Regular insulin we give people during surgery could take 45 minutes to an hour to take effect," he says.
England co-authored (along with three Echo researchers) a July 2008 study in the Journal of Diabetes Science and Technology indicating the accuracy of Symphony's blood glucose measurements was comparable with the more common practice of drawing and testing blood samples. This finding was consistent with the results of a Symphony tCGM study that Echo announced in November. Using about 900 Symphony tCGM glucose readings paired with reference blood glucose measurements (taken using blood samples), Echo claimed its technology was 97 percent accurate.
Beyond its potential impact on surgery and daily diabetes maintenance, England says continuous glucose monitoring might help doctors better understand insulin and how it works in the body. About 50 million people worldwide use insulin, according to the Joslin Diabetes Center in Boston.
The only "noninvasive" glucose meter to have received U.S. Food and Drug Administration (FDA) approval is no longer on the market. In 2001 Cygnus, Inc., won FDA approval for its GlucoWatch, which was worn like a wristwatch and designed to be used in conjunction with conventional blood testing to track trends and patterns in a patient's glucose levels. The GlucoWatch administered a small electrical charge into the wrist to bring glucose to the skin surface where it could be measured every 10 minutes. The device, however, was discontinued in 2007 after complaints about its accuracy and that it caused skin irritation in some users.
Echo is trying to succeed where the GlucoWatch did not by improving the technology's ability to permeate a patient's skin, Robert Langer, an institute professor at the Massachusetts Institute of Technology (M.I.T.), wrote in an e-mail to Scientific American. Langer would know—the basic premise of Symphony tCGM is based on ultrasonic transdermal drug delivery technology that Echo licensed from him about a decade ago. Langer's technology focused on administering drugs without needles and even received FDA approval to administer Lidocaine cream, a local anesthetic made by Ferndale Pharmaceuticals, Ltd. With Symphony tCGM, Echo is essentially testing whether this process can safely be reversed to read blood glucose levels.
Glucose monitoring is extremely important to diabetics, to the extent that even somewhat invasive systems—including those that lance a patient's fingertips to draw blood—are used by millions and have sales in the billions, according to Langer. "Everyone I speak to in the diabetes field feels (transdermal monitoring is) very badly needed," he adds.
England cautions, however, that finding an effective transdermal continuous glucose monitoring system is just one step in controlling diabetes. There still is no consensus on what constitutes the "right" glucose level in different patients, he says. Until that is determined, the benefit of having tighter control over blood glucose levels is an "open question," he adds. "We haven't had the technology to study this for any length of time."
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18 Comments
Add CommentAn FDA-approved non-invasive blood glucose monitoring system would be a tremendous advance for diabetics. But Michael England must be corrected on his last statement. There is no open-endedness to the question of whether tighter control over blood glucose levels is beneficial to long-term care, or to its importance in mitigating diabetic complications.
Reply | Report Abuse | Link to thiscloser and closer to the Star Trek Tricorder!
Reply | Report Abuse | Link to thisIn general, DRRoman is correct. However, tight control may be inappropriate for several groups:
Reply | Report Abuse | Link to this1. the elderly, since a primary risk of tight control is increased occurrence of hypoglycemia, and hypoglycemia can cause strokes and heart attacks in older people
2. those with existing diabetes-related complications - such as end-stage kidney disease or severe vision loss - since the major goal of tight control is to prevent complications many years later
4. those with coronary artery disease or vascular disease
3. individuals with hypoglycemia unawareness
Note that using a Continuous Glucose Monitor may mitigate risk in these populations. Since current CGMs measure plasma, resulting in a wider deviation from blood readings, technology like that described as being used in the Symphony could be a welcome addition.
oops switched numbering sequence (3 & 4)...
Reply | Report Abuse | Link to thisalready here: http://www.livescience.com/technology/080430-cell-phone-medical.html
Reply | Report Abuse | Link to thisand: http://www.dailytech.com/New+Miracle+Diagnosis+Handheld+Medical+Scanner+800+Times+More+Sensitive+Than+Fullsize+Scanners/article12322.htm
Another advantage of Symphony is that it is unlike today's Continuous Glucose Monitor systems, which require a second, separate insertion when used in combination with an insulin pump. Symphony does not require an insertion. That's a plus.
Reply | Report Abuse | Link to thisany improvement is to be hailed! particularly one that does no harm to you!
Reply | Report Abuse | Link to thisYes, now if it can be done AFFORDABLY.
Reply | Report Abuse | Link to thisSo the elderly will have a chance at it.
Nice article. Continuous blood glucose monitoring (CGM) is a relatively new, developing, technology that can help to provide a more comprehensive measure of glycemic excursions than intermittent self-blood finger-stick glucose monitoring (SBGM) and thus could potentially improve diabetes control. Although some controversy still exists, CGM has been found to improve glucose control in T1DM patients were it can be an important part of a patients daily disease management program.
Reply | Report Abuse | Link to thisPeter Hofland, PhD
Editor: The Diabetes Challenge http://thediabeteschallenge.ning.com
Sunvalley Communication
Chandler, AZ 85249
This technology has existed for years. The ability to profit from it has not. Hence, it was never commercialized.
Reply | Report Abuse | Link to thisI have four letters for you: DCCT. Go look it up, and then tell me again that the benefit of having tighter control is an open-ended question.
Reply | Report Abuse | Link to thisUpon closer examination, I see that England is the chief of adult cardiac anesthesia at Tufts, not an endocrinologist. I applaud the work he is trying to do, but I think the scientific community (and diabetics) would be better served if he stuck to public statements in his own area of expertise. Repeated statements like this one are enough to get insurance coverage for frequent BG testing reduced or even eliminated. As if we don't have enough trouble getting the insurance companies to pay for our care.
I strongly agree with arvengel. If healthcare was really about improving health instead of making profit, real time glucose monitoring would have been developed a long time ago. Does anyone have any idea how much profit is made from test strips, lancets, etc.? Nothing could be more overpriced.
Reply | Report Abuse | Link to thisEngland's response is misleading. While there may be higher risk for some patients in keeping tighter control of glucose, real time, more accurate reading of glucose is likely to help prevent hypoglycemia. This technology is long overdue and a hell of a lot more important than electronic medical records.
Of course, what do I know, I am not a doctor, just a type I diabetic.
I have worn an insulin pump for over 6 years. It is by far the best treatment that I have found. I tried the invasive CGM but the needle was to uncomfortable for me. (I am thin). I will be glad to see a CGM that is non invasive. I am willing to help test it any time.
Reply | Report Abuse | Link to thisBeing a diabetic that has worn an insulin pump for over 6 years, I am looking forward to this and other innovations in the future. I have tried the CGM's already out but they were to uncomfortable for me.
Reply | Report Abuse | Link to thisi believe there is some possibilities to control art attack
Reply | Report Abuse | Link to thisi styl belyve there are some multype area of development and especially in human genomY 's
Reply | Report Abuse | Link to thisThe all important thing is when will I be able to purchase one in the UK!
Reply | Report Abuse | Link to thishi how are u guys please let me know how to buy this device i try to look it up but i couldn't find it so any one know how to buy one?
Reply | Report Abuse | Link to this