Table 1.

Summary of bioinks presented here, with advantages and disadvantages for each bioink. All components are considered in their non-modified (natural) states.

Bioink	Advantages	Disadvantages
Agarose	Tunable strength	Low rates of cellular proliferation
	Tunable melting temperatures	Low cell adhesion/spreading
Alginate	Tunable strength through alteration of monomer percentages	Biologically inert
	Rapid ionic crosslinking	Limited biodegradability
Chitosan	Mucoadhesion	Poor solubility
	Hemostatic activity	Poor shape fidelity post printing
	Interactions with cell membrane
	Antimicrobial/analgesic effects
	Controllable degradation
Collagen	Enhanced cellular attachment/growth	Gelation at higher temperatures, liquid form at lower temperatures
Extracellular Matrix	Tissue specific	May be difficult to source
	Multitude of growth factors/cell adhesion points	Difficult to characterize
		Batch to batch variability
		Mechanically unstable
Fibrin	Enzymatic crosslinking	Rapid degradation profile
	Non-linear elasticity: high deformation potential	Host source may result in immune reaction
	High cell adhesion/growth/development	Poor shape fidelity pre-crosslinking
	Natural degradation	Highly viscous post crosslinking
Gelatin	Thermo-reversible gelation	Many crosslinking options are cytotoxic
	High cell adhesion/growth/development
	Can act as thickening agent/support material for other bioinks
Hyaluronic Acid	High biocompatibility	Poor mechanical properties
	Reproducible/tunable formation and degradation profiles	Slow gelation rate
		Rapid degradation profile
Scaffold-Free	High cell density	Complicated manufacturing techniques
	Rapid strand fusion	High cell density (sourcing/expanding)
	Self-assembly	Cannot be used with DLP systems
Silk (Fibroin)	Biocompatible	Hydrophobic
	Adjustable degradation	Slow gelation rate
	Mechanically stable
	Self-assembly
Silk (Sericin)	Immunologically inert	Poor mechanical properties
	Stimulated cell migration/proliferation
	Gelation at low concentrations