Table 1. 4D printing cellular scaffolds.

Category	Ink compositions	Cell	Fabrication methods	Stimuli	Possible applications	References
Cell-Iaden scaffolds	Oxidized and methacrylate alginate (OMA)	Human mesenchymal stromal cells (hMSCs)	DIW	Solvent	Cartilage-Iike tissue	[90]
	Hyaluronanj alginate	hMSCs	Extrusion-based printing	Solvent	Cartilage-Iike tissue	[122]
	Collagen	Fibroblasts	Laser-assisted bioprinting	Stress-release contraction	Soft tissue engineering	[121]
Cell-seeding scaffolds	Gel-MA, Gel-COOH-MA	Human umbilical vein endothelial cells (HUVECs)	Inkjet printing	Solvent	Mimicking microvessels	[109]
	Polyurethane	hMSCs	FDM	Temperature	Scaffolds for tissue engineering	[124]
	SMP	Neural stem cells (NSCs)	FDMj extrusion-based printing, stereolithography	Temperature	Culture substrates	[126]