Optical Oxygen Measurements Within Cell Tissue Using Phosphorescent Microbeads and a Laser for Excitation

In the field of tissue engineering, spherical phosphorescent microprobes are well suited to quantify the oxygen content in close proximity to the cells during their growth phase. When using standard seed trays like glass dishes, probe excitation and signal acquisition can be realized by applying a fluorescence microscope. However, when using a bulky bioreactor a custom-built optics system with a laser as the excitation source had to be employed. Here we describe the basic principles of spherical optical oxygen microprobes for use in standard cell cultures and the system modifications with a laser, which were required in order to perform similar measurements from a distance in bioreactor cultures.