Evaluation of a miniature blood glucose sensor

A miniature version of the electrocatalytic glucose sensor has been designed and fabricated with thick-film metalization technology. The in vitro stability tests of the sensor were performed in buffered saline, human plasma ultrafiltrate, and bovine plasma. For bovine plasma studies the sensor was directly coated with a semipermeable ethylene vinyl alcohol (EVAL) membrane. To stabilize the activity of the sensing platinum electrode, a fast-pulsing reactivation method was applied. Good performance of the continuously operating sensor was achieved in buffer (10% stability of the baseline current within 12 days) and human ultrafiltrate (10% stability of the baseline current and 5% stability of the sensitivity within 7 days). However, for measurements in plasma a slow degradation of the sensor's sensitivity (approximately 10% per day) was observed. These results indicate that when a proper screening membrane is provided the continuous glucose monitoring of body fluids with the miniature sensor is possible for at least 7 days.