“…To scale up the hierarchical arrangement, bundles of nanofibers were produced by rolling up the mats to mimic the muscle fibers ( Figures 5E,F ). By tuning the width of the starting mat, it was possible to obtain bundle diameters in the same order of magnitude of those of muscle fibers (about 100 μm) and fascicles (up to 280 μm) ( Shahinpoor et al, 2007 ; Frontera and Ochala, 2015 ; Ceylan et al, 2017 ; Klećkowska-Nawrot et al, 2018 ). To define the best compromise between morphology and mechanical performances, both random and aligned bundles were investigated.…”