Title :
Microfabricated needle-type sensors for pO2, pCO2, and pH
Author :
Wang, Xiaowen ; Suzuki, Hiroaki ; Hayashi, Katsuyoshi ; Kaneko, Takashi ; Sunagawa, Kenji
Author_Institution :
Inst. of Mater. Sci., Univ. of Tsukuba, Ibaraki, Japan
Abstract :
In order to conduct in vivo continuous monitoring of blood gas levels, very thin disposable pO2, pCO2, and pH sensors, which could be incorporated into a syringe needle or a catheter, were microfabricated. Electrode patterns were formed on a polyimide substrate and stacked with intervening polyimide insulating layers. An electrolyte layer was formed, which was covered with a silicone rubber gas-permeable membrane or a passivating layer. The most critical part of the sensor was a Ag-AgCl reference electrode with a pinhole structure. Because of the structure and novel operational mode of the reference electrode, its potential stabilized immediately, and reproducible responses were realized for the respective sensors. Performance characterization revealed clear responses and linear calibration plots in the ranges of partial pressures or pH of physiological levels. No significant damages or changes in the performance of the sensors were observed after ethylene oxide sterilization.
Keywords :
biomedical electrodes; blood; carbon compounds; electrochemical electrodes; electrochemical sensors; gas sensors; microelectrodes; microsensors; oxygen; pH measurement; silver; silver compounds; Ag-AgCl; blood gas level monitoring; electrode pattern formation; needle-type sensors; pCO2 sensors; pH sensors; pO2 sensors; passivating layer; pinhole structured electrode; polyimide insulating layers; polyimide substrates; reference electrodes; sensor microfabrication; silicone rubber gas-permeable membrane; Blood; Catheters; Electrodes; Gas detectors; In vivo; Insulation; Monitoring; Needles; Polyimides; Sensor phenomena and characterization; Blood gas; carbon dioxide; oxygen; pH; reference electrode; sterilization;
Journal_Title :
Sensors Journal, IEEE
DOI :
10.1109/JSEN.2005.853594