A Review on the Adaption of Alginate-Gelatin Hydrogels for 3D Cultures and Bioprinting

Abstract

Sustaining the vital functions of cells outside the organism requires strictly defined parameters. In order to ensure their optimal growth and development, it is necessary to provide a range of nutrients and regulators. Hydrogels are excellent materials for 3D in vitro cell cultures. Their ability to retain large amounts of liquid, as well as their biocompatibility, soft structures, and mechanical properties similar to these of living tissues, provide appropriate microenvironments that mimic extracellular matrix functions. The wide range of natural and synthetic polymeric materials, as well as the simplicity of their physico-chemical modification, allow the mechanical properties to be adjusted for different requirements. Sodium alginate-based hydrogel is a frequently used material for cell culture. The lack of cell-interactive properties makes this polysaccharide the most often applied in combination with other materials, including gelatin. The combination of both materials increases their biological activity and improves their material properties, making this combination a frequently used material in 3D printing technology. The use of hydrogels as inks in 3D printing allows the accurate manufacturing of scaffolds with complex shapes and geometries. The aim of this paper is to provide an overview of the materials used for 3D cell cultures, which are mainly alginate–gelatin hydrogels, including their properties and potential applications.

Three-Dimensional Culture of Rhipicephalus (Boophilus) microplus BmVIII-SCC Cells on Multiple Synthetic Scaffold Systems and in Rotating Bioreactors

“…Speculating that these biochemical analogs might inhibit the development of a fibrocytic phenotype, the lack of clearly observable fibroblast-like cells in hydrogels may be due to a deleterious effect of the chemical constitution of hydrogels and their finite lifetime to provide sufficient rigidity to support 3-D development. The limited experimental lifespan of hydrogels has been extended by the incorporation of silk chondroitin and other inert materials providing enhanced rigidity and stability [79].…”

“…Unlike mammalian cells, which have the property of rapid "tissue-like" development, tick cell lines like BmVIII-SCC require longer time spans that generally extend beyond the period of structural stability of existing hydrogel technology, which is approximately 40 days. The introduction of hydrogel formulations with synthetic silk fiber elements or composed of modified or synthetic collagen proteins or other materials [79] may extend their stability, making them more suitable for prolonged 3-D tick cell culture. This will exploit hydrogels' flexible composition, allowing tick cells to colonize and progress in horizontal, vertical, and tangential orientations, rendering visualization, identification, and morphometric description problematic by standard light microscopy techniques.…”

Bioprinting of Complex Multicellular Organs with Advanced Functionality—Recent Progress and Challenges Ahead

“…[59] This trend is consistent for virtually all bioprinting methods. Many strategies attempted to overcome this limitation, such as the bioprinting of biomaterials connected to syringe pumps that increased the hydration of a cell-laden hydrogels while also promoting biomaterial crossl inking, [47,[120][121][122][123] or the use of humidifiers onto the bioprinted structure, [124,125] to ensure immediate hydration and maintenance of temperature and oxygenation. Even the integration of an entire incubating system onto commercial bioprinters, equipped with UV light, temperature, and humidity control, has been reported.…”

Improving Cell Viability and Velocity in μ-Extrusion Bioprinting with a Novel Pre-Incubator Bioprinter and a Standard FDM 3D Printing Nozzle

“…The possible applications of alginate makes this material to be widely studied. Many authors are trying to enhance its poor mechanical properties while maintaining or increasing its good biocompatible properties [ 11 ]. As an example, Pan et al [ 12 ] are trying to enhance the cell viability by encapsulating the cells using an alginate hydrogel blend with pyrogallol.…”