Opportunities at the Skin Interface for Continuous Patient Monitoring: A Reverse Iontophoresis Model Tested on Lactate and Glucose

Skin has the potential to provide an important noninvasive route for diagnostic monitoring of human subjects for a wide range of applications. Dimensions of surface features in skin suggest that nanodevices and microdevices could be utilized to monitor molecules and ions extracted from the skin. Methods of enhancing extraction from the skin for diagnostics are being developed including reverse iontophoresis, electroporation and sonophoresis. A model system for the simulation of in vivo extraction of molecules and ions by reverse iontophoresis is described here that displays similar behavior to skin both in terms of molecular flux levels and electrical impedance characteristics. The device has potential for use in the development of complete reverse iontophoresis/sensor systems, allowing sensor and extraction systems to be studied and optimized before being tested in the complex in vivo environment. The system has been tested using glucose and lactate and the results are reported and discussed.