3D cell sheets formed via cell-driven buckling-delamination of patterned thin films

•Ion beam was used to control scission/crosslinking in polylactic acid.•The resultant film-on-substrate cell culture system (FoSS) consists of 3 layers.•Cells can induce wrinkling and buckling-delamination of the surface layer of FoSS.•Cells formed folds and protrusions by crumpling the peeled films within 48 h.•The 3D cell sheets can be used in tissue engineering and regenerative medicine.