Calibration of a wearable glucose sensor.
Calibration of glucose sensors proved difficult for electrodes with immobilized glucose-oxidase. The correlation between the sensitivity of the electrodes in vitro and in vivo appeared to be poor. We developed a new type of glucose sensor, based on a microdialysis system, in which an oxygen electrode is used as detector outside the body and the enzyme glucose-oxidase dissolved in water is used as a dynamic selector. The enzyme solution is pumped through a hollow fiber placed subcutaneously, before the fluid passes the detector. The glucose sensor was tested in the subcutaneous abdominal tissue of 12 healthy volunteers and 12 type I diabetic patients. Blood glucose was clamped at two levels to permit a two-point calibration of the sensor in vivo. These values correlated well with the in vitro calibration factors (r = 0.949). In subcutaneous tissue the sensor measures 43 +/- 9% of the blood glucose value, using the in vitro calibration factor. No differences were detected between healthy volunteers and diabetic patients.
Schmidt
F J
FJ
Department of Pharmaceutical Technology and Biopharmaceutics, University of Groningen, The Netherlands.
Aalders
A L
AL
Schoonen
A J
AJ
Doorenbos
H
H
D000328:Adult; D015374:Biosensing Techniques; D001786:Blood Glucose / Q000032:analysis*; D002138:Calibration; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy*; D005260:Female; D005947:Glucose / Q000032:analysis*; D015309:Glucose Clamp Technique; D006801:Humans; D015918:Infusion Pumps, Implantable; D007332:Insulin Infusion Systems; D008297:Male; D008839:Microelectrodes
D001786:Blood Glucose; D005947:Glucose