Osmium Redox Hydrogel Mediated Biosensor for Measurement of Low Concentration Glucose Extracted by Reverse Iontophoresis

An osmium redox hydrogel mediated biosensor for continuous monitoring of glucose extracted from subcutaneous solution by reverse iontophoresis has been developed. For the measurement of low concentration glucose, osmium‐poly(vinylpyridine) wiring horseradish peroxidase was introduced to modify the smooth Au electrodes, and the developed glucose biosensor exhibited a high sensitivity of 11.45 nA μM^?1 cm^?2 and a low detection limit of 2 μM, as well as a high operational stability of more than 97% of its initial activity over a test period of 13.5 h in stirred glucose solution at low applied potential (?0.1 V vs. Ag|AgCl), efficiently inhibiting the electroactive interferences. Permeability of the hydrogels was studied and a diffusion coefficient of 2.4×10^?5 cm²/s for H₂O₂ was obtained. In addition, the effects, such as temperature and the variation happening on Ag|AgCl counter electrode, on determination of glucose were also considered. The proof‐of‐feasibility of the biosensors for the monitoring of the glucose extracted from the subcutaneous solution was tested in vitro, and the responses of the sensors were analyzed. A linear response to current produced by extracted glucose in the concentration range of subcutaneous glucose from 1.0 to 12 mM was obtained with a correlation coefficient up to 0.989. These results testify the feasibility of the developed sensors for measuring the low concentration glucose and have significance for the development of noninvasive glucose monitoring system for the control of diabetes.