Gellan Fluid Gel as a Versatile Support Bath Material for Fluid Extrusion Bioprinting

Abstract

Biomedical applications of three-dimensional (3D) printing demand complex hydrogel-based constructs laden with living cells. Advanced support materials facilitate the fabrication of such constructs. This work demonstrates the versatility and utility of a gellan fluid gel as a support bath material for fabricating freeform 3D hydrogel constructs from a variety of materials. Notably, the gellan fluid gel support bath can supply sensitive biological cross-linking agents such as enzymes to printed fluid hydrogel precursors for mild covalent hydrogel cross-linking. This mild fabrication approach is suitable for fabricating cell-laden gelatin-based constructs in which mammalian cells can form intercellular contacts within hours of fabrication; cellular activity is observed over several days within printed constructs. In addition, gellan is compatible with a wide range of ionic and thermal conditions, which makes it a suitable support material for ionically cross-linked structures generated by printing alginate-based ink formulations as well as thermosensitive hydrogel constructs formed from gelatin. Ultraviolet irradiation of printed structures within the support bath is also demonstrated for photoinitiated cross-linking of acrylated ink materials. Furthermore, gellan support material performance in terms of printed filament stability and residual support material on constructs is found to be comparable and superior, respectively, to previously reported support materials.

Improving printability of a thermoresponsive hydrogel biomaterial ink by nanoclay addition

“…These effects are highly desirable for extrusion-based 3D (bio)printing technology and result in a significantly improved printability. Apart from expanding the options available to researchers for 3D bioprinting, this novel thermoresponsive hydrogel composite may also provide a new and promising material platform for other research fields, such as controlled drug delivery and release [51], versatile support bath material for fluid extrusion printing [52], sacrificial material templates in fabrication of microfluidic devices [53] and thermoresponsive self-protection [54].…”

Improving Printability of a Thermoresponsive Hydrogel Biomaterial Ink by Nanoclay Addition

“…These effects are highly desirable for extrusion-based 3D (bio)printing technology and result in a significantly improved printability. Apart from expanding the options available to researchers for 3D bioprinting, this novel thermoresponsive hydrogel composite may also provide a new and promising material platform for other research fields, such as controlled drug delivery and release, 49 versatile support bath material for fluid extrusion printing, 50 sacrificial material templates in fabrication of microfluidic devices 51 and thermoresponsive self-protection. 52…”

Granular hydrogels for 3D bioprinting applications

“…39,42 One exciting research is the simultaneous solidification of bioinks during the bioprinting process, taking the advantages of the Schiff base crosslinking between the carbohydrazide-modified gelatin bioink and oxidized alginate medium (with aldehyde moieties) suspending the gelatin microgels. 43 As an alternative to gelatin, there are other granular hydrogel supporting baths that are made of agarose, 44 gellan, 45,46 or alginate. 47,48 Those materials are cytocompatible, easy to remove without leaving significant amount residues, and not interfere with the printed cells or materials.…”

“…For gellan granular hydrogels, they could supply crosslinking agent of the enzyme to the printed precursors for hydrogel mild crosslinking. 45 In this respect, a crosslinkable gellan granular hydrogels have been developed as a supporting matrix bath. The printed materials are serving as sacrificial materials to generate engineered tissue constructs with perfusable internal channels.…”