“…To date, both natural and synthetic materials are used to realize 3D cell systems [ [19] , [20] , [21] ]. Natural materials (i.e., collagen, gelatin, chitosan, HA, heparin alginate, silk and decellularized tissue matrices) are inherently biocompatible exhibiting good cellular interactions, low immunogenicity, and mild antigenic properties, but show poor mechanical properties, high production costs, and low reproducibility [ [22] , [23] , [24] , [25] ]. On the other hand, synthetic polymers (i.e.…”