Oxygen monitoring in a liver on a chip to study effect of drugs and nutrients

A nice collaborative paper from Stelzle, Gebhardt and Mayr labs in U. of Tübingen, Leipzig University and TU Graz monitoring oxygen and liver tissue metabolism in a well-plate format organ on a chip system. They used oxygen patches and optical fibers to monitor oxygen levels in the medium around the liver tissue made from primary human hepatocytes.

Results
They refreshed the medium every 14 h by adjusting the medium height levels in the reservoirs. The authors monitored the oxygen in the medium inside the liver on a chip and studied the effect of nutrients, fructose among others, on hepatocyte energy metabolism. They found out that fructose can have adverse effect on cellular respiration. Moreover they concluded that flow rate can be considered as an important factor to balance oxygen consumption.

Digestible of the paper Busche, M., et al. (2022). “Continous, non-invasive monitoring of oxygen consumption in a parallelized microfluidic in vitro system provides novel insight into the response to nutrients and drugs of primary human hepatocytes.” EXCLI journal 21: 144. This paper is reproduced under  https://creativecommons.org/licenses/by/4.0/. The image of the chip was edited for better clarity, data in the table and text were compiled and interpreted by AZAR Innovations.

Method
The authors used HepaChip-MP with 24 independent cell culture chambers in wellplate format, an automated dielectrophoresis process assembled viable cells into elongated micro tissues
Fabrication method: The chip was bought from Microfluidic ChipShop
Cell incorporation: Cell suspension was infused to the chip
Perfusion/refreshing method: Continuous perfusion of the cell culture chambers by gravitational driven flow
On-chip read-outs: On-chip monitoring, Sensors, Oxygen sensor, End-point microscopy

Strong points:
+ Real-time monitoring of oxygen consumption.
+ Integrated electrodes
+ Biocompatible low adsorption materials

Nothing is perfect! The system can also improve:
– Manual perfusion
– Variable flow rate
– One optical fiber for each chip, so 24 wires connected to the plate

Conclusion and outlook
This paper offers a state-of-the-art platform which enables online oxygen monitoring integrated with dynamic cell culture conditions.

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