Researchers in New Mexico have developed an implantable sensor that can simultaneously monitor glucose and insulin levels in the blood to help patients with diabetes better manage their disease.

Diabetics currently measure their glucose levels at intervals using monitors that analyze a drop of blood. The researchers say a monitor that constantly measures the ratio between glucose and insulin could help diabetics maintain closer control of their condition.

Researchers used electrochemistry and computer technology to integrate glucose and insulin monitoring into a device that can gather both kinds of data through one small, implantable needle that operates as a sensor.

To develop the sensor, scientists filled a needle with two tiny lengths of tubing that collect electrochemical data on glucose and insulin levels and transfer it to a computer. All of this happens in real time, while the device is implanted.

Although the sensor is still in very early stages -- the needle was tested while hooked up to a machine that simulates fluctuating levels of glucose and insulin production. The trend is to replace the widely used glucose-monitoring strip with implantable devices. It is very important for patients to be able to measure the ratio between insulin and glucose.

There are more than 15 million people in the US who have diabetes, and another 800,000 are diagnosed with the disease each year, according to the American Diabetes Association.

Roughly 95% have type 2 diabetes, where the body loses its sensitivity to insulin, the hormone that regulates blood glucose levels. People with type 1 diabetes, by comparison, do not produce insulin. Over the long term, high blood sugar levels can damage the eyes, kidneys, and nerves.

To combat these imbalances, patients can be prescribed insulin injections and other medicines. Some people, particularly those with type 1 diabetes, use insulin pumps to deliver insulin via a tube to the fat under the skin.

Analytical Chemistry February 15, 2001