Analytical Sciences

In vitro and Short-term in vivo Characteristics of a Kel-F Thin Film Modified Glucose Sensor

Sun Kil KANG,* Ran-A JEONG,* Sejin PARK,* Taek Dong CHUNG,** Sunmin PARK,*** and Hee Chan KIM* 

*Department of Biomedical Engineering, College of Medicine and Institute of Medical and Biological Engineering, Medical Research Center, Seoul National University, Seoul 110-744, Korea
**Department of Chemistry, Sungshin Women's University, Seoul 136-742, Korea
***Department of Food and Nutrition, Hoseo University, Asan 336-795, Korea

A new outer layer composition, consisting of polytetrafluoroethylene (PTFE), Kel-F oil, and Nafion, is suggested to minimize the detrimental effect of dissolved oxygen and to extend the linear response range of a glucose oxidase(GOx)-based sensor using nonconducting polymer. The morphology of Kel-F/PTFE/Kel-F/Nafion polymeric laminate was followed during fabrication by SEM. When Kel-F film was formed on the PTFE outer layer, the linear response was extended to 21 mM, at a sensitivity of 2.8 ± 0.8 nA/mM mm². We demonstrate that a sensor without Kel-F/PTFE/Kel-F/Nafion outer layer is relatively oxygen dependent, whereas by comparison a sensor with Kel-F/PTFE/Kel-F/Nafion outer layer is oxygen independent. The current of such a glucose sensor implanted in the subcutaneous tissue stabilized within 60 min, and the lag between blood glucose changes and sensor output was within 1 min. The in vivo characteristics of the glucose sensor described show great promise for one-point in vivo calibration.

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