New Optical Glucose Sensor

Researchers led by Gerald Loeb, a biomedical-engineering professor at the University of Southern California, are now working on a glucose-sensor design based on optical technology. A hair-like optical fiber is implanted in the skin to make frequent glucose measurements easier for diabetics.

The technique involves measuring the change in fluorescent emissions that occur when glucose binds to certain molecules. The sensor is a tiny optical fiber that could be implanted in a patient's skin. Attached to the end of the fiber inside the skin is a polyethylene-glycol polymer matrix interspersed with pairs of tightly bound chemicals, each tagged with a different fluorescent molecule. Under ultraviolet light, the bound molecules shine at one wavelength. When the researchers place the matrix in a glucose solution, glucose molecules knock out and replace one of the chemicals, dextran. As a result, the chemical complex starts emitting at two different wavelengths. The ratio of the fluorescence intensities at the two wavelengths is in proportion to the glucose concentration.

Fiber-optic system has been tested in glucose solutions and has found that it is sensitive to the range of glucose concentrations that are found in the human body.

Once the optical glucose sensor is tested in animals, it would need to go through clinical trials, which can take four to five years. If everything goes as planned, the sensors could be available as products in five to ten years.