3D printed biopolymer with micro-/nano-scale structures. (a,b) Electrohydrodynamically printed drug-loaded polycaprolactone (PCL) polymer patches and drug-loaded PCL–polyvinyl pyrrolidone (PVP) patches after 90 mins drug release, reprinted from [48] with the permission of Nature Publishing Group, Copyright 2017; (c,d) SEM images of electrohydrodynamically printed polyethylene oxide (PEO)–PCL scaffolds with multiwall carbon nanotube (MWCNT) content of 0.5 w/v%, reprinted from [55] with the permission of IOP Publishing, Copyright 2017; (e,f) SEM characterizations of melt electrohydrodynamic 3D-printed cell scaffold constructs cultured for 7 days; (e) SEM images of cell morphology in the scaffolds with a fiber spacing of 250 μm; (d) SEM images of cell morphology in the scaffolds with a fiber spacing of 100 μm, reprinted from [56] with the permission of IOP Publishing, Copyright 2017.