Fluorimetric oxygen sensor with an efficient optical read-out for in vitro cell models

•An efficient optical read-out for the fluorescence stemming from thin dye-polymer films deposited on glass substrates is presented.•With the help of the numerical simulation results, the read-out can be optimized to different film thicknesses.•The optical scheme facilitates total internal reflection excitation, which reduces the excitation power radiated into the sample side.•The set-up can be especially useful when biocompatibility is important, and the dye concentration and the excitation power must be minimized.•The set-up is successfully applied to the pO2 stress testing of beating human iPS cardiomyocyte aggregates.