Continuous glucose monitoring system (CGMS) using implantable glucose sensor have provided significant benefit on the management of diabetic health care, since it can present not only the point of glucose degree but also its trend. Although the present glucose degree is same, rising and lowering phenomenon of blood glucose lead to an opposite treatment action. In addition, daily trend observation is useful for the evaluation and improvement of individual pharmacotherapy.  However, since sensor device of CGM at a present day requires a length of 1 cm to be inserted in skin, development of a lower-invasive CGMS is expected for the improvement of diabetic patients’ quality of life.

    In this study, a fine tapered needle shape glucose sensor, which has sensing region at the tip of a fine tapered electrode, was proposed.  Since the sensing region is at the tip of tapered electrode, it only requires the sensor tip to be implanted in the tissue for glucose monitoring. In other words, it can be possible to perform as a patch type sensor, which impresses the user as a sticking sensor instead of a implanting sensor.  Fine platinum-iridium alloy wire with a diameter of 0.17 mm was placed inside the tapered PEEK tube and glucose oxidase (GOx) was immobilized on the surface of platinum electrode by using the combination of electrodeposition and electropolymerization technique. Ag/AgCl film was prepared on the outer surface of PEEK tube in order to be employed as reference electrode together as counter electrode.  Glucose sensor properties of the obtained GOx-immobilized electrode were evaluated by using in vitro and in vivo measurements. A patch type sensor with insert length of 1 mm was implanted in a rabbit. Clear sensor response corresponding to glucose concentration change was confirmed.