One major limitation of tissue engineering approaches is the insufficient supply of the cells with oxygen due to a lack of a functional vascular system ex vivo. In complex 3D culture systems, such as bioprinted constructs with clinically relevant dimensions (Kilian D. MRS Bull. 2017; 42: 582-592), the local O ₂ concentration depends on the macroporosity of the hydrogel scaffold as well as on the permeability of the hydrogel material (bioink) which oxygen has to pass through via diffusion. For better understanding new tools are needed to monitor in real time oxygen distribution dynamics within bioprinted constructs. We propose utilisation of cytocompatible O ₂ sensitive luminescent nanoparticles (NP) for this purpose.