Design of a Biosensor for Continual, Transdermal Glucose Monitoring

Abstract

The Diabetes Control and Complications Trial (1) and other trials have shown that frequent monitoring of blood glucose by diabetics is critical to achieving normoglycemic concentrations. The ability to achieve this goal is hampered, however, by the lack of any means of obtaining frequent blood glucose data in a convenient and unobtrusive manner. To address these needs, a continual, noninvasive glucose monitoring system has been developed that utilizes reverse iontophoresis to induce an electroosmotic flux of glucose through intact skin. The electroosmotic glucose flux (measured ex vivo by HPLC) was shown in earlier clinical trials to correlate with the blood glucose concentrations (2). To create a miniaturized and wearable system, an amperometric biosensor has been developed that measures in situ the glucose extracted through the skin into a hydrogel pad to provide periodic measures of blood glucose every 20 min over the course of 12 h. A diagram of this system is shown in Fig. 1⇓ A. Figure 1. Schematic of the GlucoWatch biographer ( A ) and evaluation of stability of glucose extraction and measurement in cadaver skin diffusion cell over 12 h (36 measurements) at 500, 1000, and 4000 mg/L (50, 100, and 400 mg/dL; B ). …