Monitoring tissue oxygen heterogeneities and their influence on optical glucose measurements in an animal model

Abstract

The purpose of this study was to characterize the heterogeneity of oxygen partial pressure in different adipose tissue zones and to assess the possibility of compensating these heterogeneities during optical glucose measurements. In this proof of concept study, the heterogeneity of oxygen partial pressure was determined in the adipose tissue of a pig by using 48 oxygen sensors in 3 zones of the abdominal region at two different blood oxygen levels. Sensor oxygen values correlated well with reference blood oxygen values and we identified heterogeneities in oxygen partial pressure among the defined zones of the abdominal region. Significant differences in the mean oxygen partial pressure were found when comparing the three abdominal zones but no significant differences were found when comparing two sensors located in close proximity (on one cannula). The low heterogeneity on one cannula allows the compensation of physiological oxygen variations for optical glucose measurements by using an additional oxygen sensor in close proximity to the glucose sensor. In addition, this setup can be used to continuously monitor tissue oxygenation e.g. in patients with adipose tissue dysfunction or serve limb ischemia.

Development of Organs-on-Chips and Their Impact on Precision Medicine and Advanced System Simulation

“…Optical sensors can detect a limited range of substance concentrations; for example, when detecting pH, they require the addition of absorbable phenol red for colour development and, only in the pH range of 6.5–8.0, linearity reflects well and data are accurate [ 95 , 96 ]. However, optical sensors are advantageous in low-oxygen environments because their measurement data are independent of redox reactions [ 97 , 98 ].…”

NIR Phosphorescent Intramolecularly Bridged Benzoporphyrins and Their Application in Oxygen-Compensated Glucose Optode

“…However, the signal of these sensors is affected by oxygen fluctuations in the sample, resulting in necessity of an additional detection of the oxygen partial pressure . This, for instance, can be realized with help of an array of fiber-optic oxygen and glucose sensors. − Such solution, however, neither enables subcutaneous glucose monitoring through skin nor compensates for microheterogeneities in oxygen distribution in tissues. , …”

“…11−13 Such solution, however, neither enables subcutaneous glucose monitoring through skin nor compensates for microheterogeneities in oxygen distribution in tissues. 14,15 Evidently, conventional UV−vis indicators are not suitable for subcutaneous measurement due to strong light scattering by the tissue, efficient light absorption by skin pigments and hemoglobin as well as strong autofluorescence. Oxygen indicators operating in the so-called NIR optical window 16 overcome the above limitations.…”