By: Russell Phillips
Fingertip blood-oxygen monitors, called pulse oximeters, measure oxygen in the blood using light and color. The noninvasive device, which clips onto a fingertip or earlobe, typically has a pair of light-emitting diodes (LEDs) facing a sensor. Light of a certain wavelength (a certain color) travels through a translucent part of the body like the fingertip or an earlobe, and is picked up by the sensor. The amount of oxygen in the blood (actually, oxygenated hemoglobin) affects how much light from each diode finally makes it through the finger and reaches the sensor. The result is an effective measurement of the amount of oxygen in the blood.
A similar, no-finger-sticking-procedure using light and color for measuring the amount of glucose in the blood would be great, but the wavelengths of light that indicate glucose can’t be detected through the skin. One idea scientists have proposed is using a glucose-sensitive material and implanting it just under the skin.
The glucose-sensitive material would change color depending on the amount of glucose in the blood and reflect the changes in color to a reader worn by the user. Sound like science fiction? Well, it may be a reality in the not too distant future. The materials needed have already been developed, and the sensor’s color-changing abilities have been demonstrated in the lab.
Professor Arthur Epstein and doctoral student Louis Nemzer at Ohio State University have been working on attaching an enzyme that changes color in response to glucose concentration to a biocompatible (easily accepted by the body) polymer previously developed in Epstein’s lab. Nemzer is studying the optical properties of polyaniline nanofibers, which may be used to make optical biosensors, like a continuous glucose monitoring system.
Licensing the technology is the next step, followed by more research in the lab and then on to humans!
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