Sweet Sensing

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Science  06 Aug 2010:
Vol. 329, Issue 5992, pp. 611
DOI: 10.1126/science.329.5992.611-b

Diabetics face the daily challenge of determining their glucose levels, which can fluctuate because of changes in diet, exercise, insulin intake, medications, and other factors. Gough et al. have engineered a sensor that could be implanted in pigs to transmit their glucose levels for over 1 year. Two enzymes, glucose oxidase and catalase, were immobilized within a cross-linked protein gel to transform glucose and oxygen into gluconic acid. Changes in oxygen level were then measured with a differential sensor, relative to background levels, ensuring that the device could work across a wide range of oxygen concentrations. A nonporous polydimethylsiloxane layer allowed for oxygen diffusion while preventing poisoning of the sensor by other compounds. Under diabetic conditions, the sensors accurately tracked fluctuations in glucose levels, but with time delays of approximately 10 min. The primary cause was the limit on the diffusion rates of glucose through the tissues.

Sci. Transl. Med. 2, 42ra53 (2010).

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