CELLINK® A Bioink is based on the naturally derived polysaccharide, alginate. Isolated from the cell walls of brown algae, alginate is a versatile biomaterial that has been utilized in diverse applications ranging from food to drug delivery. Alginates contain source dependent arrangement of (1-4)-linked-D-mannuronic acid (M units) and -L-guluronic acid (G units) monomers which comprise the alginate block polymer. The introduction of divalent cations such as Ca2+ bind G-units in adjacent chains together to rapidly form a gel. Alginates biocompatibility, ease of use, and customizability has resulted in the wide applicability of the material in many tissue engineering applications including bone and cartilage, along with cell and drug delivery. Additionally, the alginate can be readily modified to contain nearly any peptide sequence permitting the fabrication of cell-specific biomaterials to guide cell differentiation and tissue formation. Alginate is one of the most commonly bioinks being utilized in the bioprinting field, being utilized as a standalone bioink and as a base material for composite bioinks.