Dual sensor could provide early warning for diabetics

Diabetics could benefit from a new sensor that measures the glucose-insulin ratio.

According to Joseph Wang, a professor at New Mexico State University in Las Cruces, NM, tracking insulin levels as well as glucose could help diabetics stave off fatigue and more serious complications such as kidney failure and heart disease.

Insulin is the hormone that allows glucose (blood sugar) to enter cells and convert foods into energy to sustain life. When insulin fails to ‘unlock’ cells, glucose builds up in the blood and cells die. Hazardous conditions can occur when blood contains either too little or too much glucose.

Glucose sensors and insulin pumps have been used for nearly a decade to measure and remedy imbalances in blood sugar levels. The sensor detects excess glucose while the pump acts as an artificial pancreas – the organ that produces insulin in the body. Another device known as an insulin detector estimates the amount of the hormone in the blood.

Combining two types of sensors in such a small device was a complicated task, Wang said. Glucose is measured in the milli-molar range, while insulin is tracked on even smaller nano-molar levels – a fivefold difference in magnitude. In addition, each must send an electrical signal without interference to a minicomputer that, ideally, can calculate, store and display information, he added.

Employing methods similar to those used to create existing implants, the researchers designed a needle-shaped sensor that can be implanted in the body. The next step is to halve the size of the sensor, reducing it to the thickness of 26-gauge wire (about the size of a hypodermic needle).

The research was funded by a research grant from the US National Institutes of Health and the findings were reported in the February 15 issue of Analytical Chemistry, a peer-reviewed journal of the American Chemical Society.