Table 1.

Overview the 3D printing technologies

	Technology	Power source	Printing materials	Print speed	Particle size		Layer thickness		Ref.
Cell-free	DED	Laser/electron beam	Metal	Fast	25–75 μm		250 μm		[40, 41]
	SLS	Laser beam	Metal/ceramic/polymers	Slow	50–150 μm		20–100 μm		[42]
	SLM		Metal		20–60 μm				[24, 36, 39]
	EBM	Electron beam	Metal	Fast	45–105 μm		50 μm		[39]
	Binder jetting	Thermal source	Metal	Medium (6–14 mm/s)	Submicron–150 μm		15–300 μm		[25]
	FDM	Thermal	Thermoplastics; polymer-metal composites	Slow (200 µm–10 mm/s)	–		100–200 μm		[26, 35]
					Viscosity	Cell viability	Resolution	Cell density
Cell-free/cell-laden	SLA	UV	photopolymers	Fast	None	>90%	60–150 µm	<108 cells/ml	[22, 27]
	DLP	UV/visible light	photopolymers	Fast than SLA		Higher than SLA	25–50 µm		[28–31, 34]
Cell-laden	Inkjet bioprinting	Thermal/piezoelectric	Thermoplastics	Fast (1–104 droplets/s)	Low (3.5–12 mPa/s)	>85%	75 µm	<106 cells/ml	[9, 28]
	Extrusion bioprinting	Pneumatic/pressure	Natural/synthetic polymers	Slow (10–700 mm/s)	High (30–6 × 107 mPa/s)	80–90%	200–1000 µm	>108 cells/ml	[21]