Table 2.

Common 3D bioprinting modalities.

3D bioprinting modality	Description	Resolution range	Advantages	Disadvantages	Applications	Refs.
Conventional extrusion bioprinting	Compressed air or mechanical screw or piston drives the bioink through a nozzle	100–2000 μm	Multi-material bioprinting; high scalability; high cell density; cost-effective	Nozzle clogging; moderate cell viability due to shear stress	To biofabricate 3D tissue structures in a layer-by-layer manner	[247, 248, 265–267]
Co-axial bioprinting	Simultaneous extrusion of bioinks and crosslinker solution through coaxial nozzle	200–2000 μm		Complex setup; challenges in tuning flow rates for each bioink simultaneously	To biofabricate standalone solid or hollow tubular fibers	[249, 268–272]
Embedded bioprinting	Extrusion of bioink into supportive bath into a support bath that holds the bioprinted structure.	~20 μm		Challenges in removal of support matrix; may require additional processing steps	To biofabricate complex tissue structures using mechanically weak bioinks	[249, 276–279, 283]
Chaotic bioprinting	Chaotic flow of two or more bioinks using a nozzle equipped with a Kenics static mixer	~10 μm		Nozzle clogging; moderate cell viability due to shear stress; not suitable for high-viscosity bioinks	To generate continuous fibers with internally aligned lamellar microstructures	[294, 295, 300–302]
Inkjet-based bioprinting	Electrically heated printhead or piezoelectric actuator ejects small droplets of bioink out of the nozzle	~50 μm	High bioprinting speed; precise deposition of bioink droplets; cost-effective	Low cell viability; non-uniform droplets; printhead clogging; requires low cell density and low viscosity bioinks	To biofabricate tissue scaffolds by precise placement of small droplets of bioink onto a substrate	[250, 303–305, 308, 312, 314–316]
Stereolithography	Either single- or two-photon laser and raster scanning selectively that cures a bioink in a point-by-point manner	~1 μm	Nozzle-free; relatively fast bioprinting speed; high cell viability	Requires photocurable bioinks; moderate cost	To biofabricate tissue structures by exposing bioink to the laser that selectively cures a bioink in a point-by-point manner	[317–320]
Digital light processing	Either UV or visible light prepatterned from a projector selectively that cures the bioink in a layer-by-layer manner	~35–100 μm			To biofabricate tissue structures by exposing light through a digital mask or pattern onto the surface of the bioink in a layer-by-layer manner	[256, 318, 329, 330]
Volumetric bioprinting	Simultaneous exposure of UV or visible light onto a rotating vat of bioink that creates a desired structure in a single step	~40–100 μm			To biofabricate geometrically complex tissue construct in a centimeter-scale in a single step.	[253, 336–339]
Laser-assisted bioprinting	Precise deposition of the bioink onto a substrate using laser pulses	~10–100 μm	High precision; relatively fast bioprinting speed; high cell density	Limited cell viability; requires high-viscosity bioinks; comparatively high cost	To facilitate tissue regeneration via bioprinting using single cells or cell aggregates	[258, 345, 351, 352]
Kenzan bioprinting	Precise positioning of spheroids within a microneedle array to fused into tissue constructs	Spheroids of ~500 μm in diameter are fused to form larger tissue constructs	High cell density; high cell viability; may not require supporting biomaterial scaffold	Requires pre-fabrication of spheroids; complex bioprinting setup; may induce damage due to needle	To biofabricate tissue structures utilizing cell spheroids as the fundamental building blocks	[262, 356, 357]