Applications of Alginate-Based Bioinks in 3D Bioprinting

Abstract

Three-dimensional (3D) bioprinting is on the cusp of permitting the direct fabrication of artificial living tissue. Multicellular building blocks (bioinks) are dispensed layer by layer and scaled for the target construct. However, only a few materials are able to fulfill the considerable requirements for suitable bioink formulation, a critical component of efficient 3D bioprinting. Alginate, a naturally occurring polysaccharide, is clearly the most commonly employed material in current bioinks. Here, we discuss the benefits and disadvantages of the use of alginate in 3D bioprinting by summarizing the most recent studies that used alginate for printing vascular tissue, bone and cartilage. In addition, other breakthroughs in the use of alginate in bioprinting are discussed, including strategies to improve its structural and degradation characteristics. In this review, we organize the available literature in order to inspire and accelerate novel alginate-based bioink formulations with enhanced properties for future applications in basic research, drug screening and regenerative medicine.

Advanced Polymer Designs for Direct‐Ink‐Write 3D Printing

“…For example, when the naturally occurring biopolymer alginate is mixed with Ca 2+ salts, multivalent coordination is established between the carboxylate groups of alginate and the metal cations, affording a viscoelastic hydrogel . Shu et al.…”

“…For example, when the naturallyo ccurring biopolymer alginate is mixed with Ca 2 + salts, multivalent coordination is establishedb etween the carboxylate groups of alginatea nd the metal cations, affording av iscoelastic hydrogel. [80,81] Shu et al developed [55] am ulti-step method to 3D print complex, cellladen alginateh ydrogels tructures with good mechanical properties ( Figure 4a). Ap artially Ca 2 + -cross-linked alginateh ydrogel was prepared by using 4wt% of alginate and 0.4 wt %o f CaCl 2 forD IW.T he extruded structure was gradually immersed in as olution of CaCl 2 during the DIW process to increase the supramolecular cross-linking density,t hereby forming ar obust self-supportive 3D architecture.…”

A Bioprinted In Vitro Model for Osteoblast to Osteocyte Transformation by Changing Mechanical Properties of the ECM

“…First, two different calcium chloride solutions (0.1 and 1 m) were printed, with printing speeds of 1000 and 2000 mm sec −1 , respectively, on chromatography paper. [26,27] These hydrogels crosslink immediately upon contact with the paper and reside on top of it thus giving it mechanical properties independent of the paper. The papers were allowed to dry overnight.…”

Engineered 3D Polymer and Hydrogel Microenvironments for Cell Culture Applications

“…Using visible light, hydrogelation was induced in a mixture of alginate, tris(bipyridine)ruthenium(II) chloride and sodium persulfate. Visible light not only has less toxic and adverse effects on encapsulated cells, but also has deeper penetration depth for thicker constructs [246,247].…”