Glucose Monitoring: Surgical and Semi-invasive Devices

If your fingers are bruised and battered from multiple daily fingersticks using traditional glucose meters, rest assured that the market is buzzing with new methods for determining blood sugar levels.  The new technology ranges from implantable devices to patches to optical lenses which determine sugar levels in tears.  This post focuses on surgical and semi-invasive devices.  Part 2 will highlight non-invasive solutions.

Surgical/Semi-invasive Devices

Attempts to create long term implantable glucose monitors have been stymied in the past by the body’s natural reaction to foreign objects. When a monitor is implanted, the body responds by coating the object with a protective layer which then impedes the efficacy of most monitors within several days.

GlySens developed a long-term continuous glucose monitoring system called ICGM in which a continuous glucose sensor is surgically implanted in the abdomen and links to an external display monitor.  Whereas less successful implantable continuous glucose monitors rely on the reaction of glucose with oxygen to determine glucose levels,  (a reaction which becomes difficult to measure once the body “coats” the foreign object), the GlySens ICGM  works by detecting tissue oxygen and calculating glucose based on the measured oxygen content. The sensor is approximately the size of a thumb drive and is implanted under the skin for year long stretches.

  GlySens hopes to move towards FDA regulatory filing by 2017. Down the road, the company also hopes to integrate these sensors into insulin pumps.

Along similar lines, Senseonics developed another  implantable continuous glucose monitoring system.  A sensor is encased within biocompatible material which helps prevent the body’s natural response to a foreign object.

It is implanted subcutaneously in the upper arm or abdomen for up to six months. A transmitter is worn over the implanted sensor to activate the measurement of glucose, and glucose readings are transmitted to a smartphone via Bluetooth.  The product is currently being tested in clinical trials.

Finally, Kumetrix improved on the pre-existing standard of multiple daily fingersticks by developing silicon microneedles the size of a human hair which draw blood for glucose testing in a painless fashion.  The system consists of a hand-held meter which holds a cartridge loaded with up to 10 disposable sampling devices containing the microneedles.  The microneedle penetrates the skin and draws a drop of blood that is 1/100 the size of an average drop of blood.  Chemical reagents within the microneedle then combine with the blood to produce a distinct color. Finally, the monitor analyzes the color using a laser and determines the glucose level from the analysis.

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