Noninvasive Diabetes Monitoring through Continuous Analysis of Sweat Using Flow-Through Glucose Biosensor

We propose monitoring of diabetes through continuous analysis of undiluted sweat immediately after its excretion using a flow-through glucose biosensor. The used biosensors are based on Prussian Blue and glucose oxidase immobilized in perfluorosulfonated ionomer or gel of alkoxysilane; the resulting sensitivity with the latter reaches in batch mode 0.23 A M-1 cm(-2), and the calibration range is from 1 mu M to 1 mM (flow-through mode). On the basis of the glucose tolerance test known to be a clinically relevant procedure to mimic hyperglycemia, a positive correlation between the rates of glucose concentration increase in blood and in noninvasively collected sweat has been observed (r = 0.75). The observed correlation between sweat and blood considering low-molecular weight metabolites is even better than that observed previously between capillary and vein blood, confirming diagnostic value of sweat for diabetes monitoring. The dynamics of sweat glucose concentration, recorded by means of the proposed biosensor, is in a good accordance with the dynamics of blood glucose content without any time delay, thus offering a prospect for noninvasive monitoring of diabetes.