Image-based monitoring of oxygenation in microfluidic cell culture

Microfluidic devices have been established as versatile platforms to mimic various culture conditions or microenvironments in 2D and 3D tissue models. Oxygen availability in the cellular microenvironment strongly affects the cellular phenotype and metabolism. Therefore, monitoring oxygen tension inside microfluidic devices is essential, as it brings the in vitro conditions closer to real physoxia in cell culture and provides the basis for more reproducible and standardized results with maximal physiological relevance. Many commonly used measurement techniques for oxygen monitoring are not applicable in such small volumes, consume oxygen during the measurement process, or directly affect the cells. The use of optical oxygen sensors, based on the principle of dynamic luminescence quenching, overcomes these drawbacks. These sensors are small, and the signals are recorded in the form of visible light, so that data acquisition from the outside through the transparent walls of microfluidic chips is easily accessible. In this study, we use a 2D sensor readout system, called VisiSens, along with planar optical oxygen sensor foils integrated in microfluidic channels to investigate oxygenation in microfluidic cell culture.