Table 1.

Problems and given solutions of using alginate as a bioink in different three-dimensional (3D) bioprinting applications.

3D Bioprinting Application	Problem (of the Use of Alginate)	Solution	Reference
General	Immunogenicity (low cell grow support)	Use a low amount of d-mannuronic acid	[15]
General	Fast gelation needed	Use multivalent cations 1	[16]
General	Slow degradation kinetics	Tune the weight percent	[24]
General	Slow degradation kinetics	Oxidation	[23,49]
Vascular tissue	Lack of channels transporting oxygen and nutrients to cells	Use coaxial printing nozzles	[28,29,31]
Bone	Poor mechanical properties	Combination with hydroxypatite	[33]
Bone	Poor mechanical properties	Combination with polycaprolactone	[34]
Bone	Poor adhesion properties	Addition of adhesion peptides (Arg-Gly-Asp)	[39]
Cartilage	Need of biomimetic ECM 2	Combination with polycaprolactone 3D constructs	[42,47]
Cartilage	Need of biomimetic ECM 2	Combination with nanofibrillated cellulose	[44]
Cartilage	Need of biomimetic ECM 2	Combination with acrylamide	[45]
Cartilage	Low printability of alginate sulfate	Combination with nanocellulose	[46]
Cartilage	Low ECM 2 formation	Combination with polycaprolactone and growth factors (TGFβ)	[43]

¹ As the widely used Ca²⁺; ² ECM: extracellular matrix.