Live cells can form multifunctional and environmentally responsive multiscale assemblies of living and non-living components. We recently reported the results of a unique approach to introduce supplementary properties, fluorescence in particular, into fibrillar proteins produced by live fibroblasts and extruded into the ECM. In this work, we demonstrate that the physiological secretion of fluorescent nanostructured microfibers upon the spontaneous uptake of the appropriate fluorophore extends to living cells derived by different tissue contexts. We also show that live cells seeded on fluorescent microfibers have a different fate in terms of the cellular morphology, cytoskeleton rearrangement and viability. These results suggest that the microfibers, which are biocompatible and biodegradable, can be used as multiscale biomaterials to direct the cell behaviour.