Implantable osmotic-pressure-based glucose sensor with noninvasive optical readout

Continuous monitoring of the glucose level is a key technology for improved diagnosis and therapy of Diabetes Mellitus patients. Non-invasive optical measurement techniques at the Anterior Chamber of the eye suffer from the lack of intensity of reflected light and the very small magnitudes of the optical effects. Hence using higher magnitude physical and/or chemical effects as primary effects and using non-contact optical readout increases feasibility for in-vivo measurement systems substantially. Hence this article proposes a miniaturized micro structured measurement cell covered by a semi permeable diaphragm to be implanted micro invasively into the anterior chamber of the eye. Osmotic pressure within this cell depends on the intraocular glucose concentration and is translated into deformation of the diaphragm which is measured using white light interferometry. A bio-compatible micro structured interference filter has to be added on parts of the diaphragm to ensure high reflection properties crucial for optical deformation measurement. The article also discusses the special requirements of in-vivo measurements for the optical measurement system.