C8.2 - Optochemical Sensor Intrumentation for Continuous Monitoring of Abdominal Oxygen Tension by Microdialysis

SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
Proceedings SENSOR 2011
C8 - Bio-Chemo Sensors
A. Bizzarri, M. Cajlakovic, M. Suppan, V. Ribitsch - JOANNEUM RESEARCH Forschungs¬gesellschaft mbH, Graz, (Austria)
506 - 511


The continuous monitoring of adipose tissue oxygen tension (pO2) in patients affected by obesity and type 2 diabetes is of high importance. Low levels of oxygen tension in adipose tissue may indicate an inflammatory status and play a decisive role in the development of insulin resistance from the patient.
Optochemical sensor technology combined with microdialysis is particularly suitable for the development of minimally invasive instrumentation for medical application. We report about an optochemical sensor system based on the principle of the phase modulation fluorometry. An oxygen sensitive membrane is inserted in a miniaturised flow through cell (volume app. 5μl) and is interrogated by means of a fiber optic instrumentation integrated with the processing electronic unit. The interstitial fluid is extracted from the adipose tissue by means of a commercially available microdialysis catheter. In order to prevent the ambient oxygen diffusion using commercially available microdialysis catheter, the outlet of the catheter was replaced by a Steeltubing. The biological fluid is afterwards pumped at a flow rate of 1 ml/min into the flow through cell with inserted oxygen sensitive membrane, which emits a luminescence signal dependent on the dissolved oxygen tension in the interstitial fluid.
This sensor instrumentation has been extensively validated both in laboratory and in clinical tests. It shows a resolution better than 1 mmHg and accuracy better than ±1 mmHg over the whole measurement range of 0 – 300 mmHg. The response time including the flow time of the interstitial fluid from the catheter to the sensitive membranes is of about 10 min.