Alginate-based bioink for organoid 3D bioprinting: A review

Abstract

As a 3D cell culture, organoids have been researched thoroughly to model the human biology system in advancing disease treatment and drug development. A novel way to create an organoid is using bioink, consisting of polymeric materials and living cells, to fabricate a hydrogel scaffold through the 3D bioprinting method. Alginate has the potential to be developed as a bioink due to its good biocompatibility, low toxicity, and ease of processing method. However, studies are still required to obtain an optimum alginate-based bioink. Alginate is insufficient in terms of the cell-binding site; thus, mixing it with supplementary gelatin material can be employed to optimize further the printability, mechanical properties, and biocompatibility of alginate-based bioink. The addition of gelatin material, in addition to increasing the binding site, also makes the process of making bioink easier due to the thermoresponsive nature of gelatin. The alginate-based bioink can be further optimized depending on gelatin concentration to produce appropriate density and rheological value of bioink. The addition of gelatin into alginate-based bioink will also significantly affect the printability of bioink and the mechanical properties of resulted hydrogel scaffold, which need to be considered appropriately. The alginate-based bioink also showed good biocompatibility regarding cell viability and biological performance. This paper focuses on the relationship between the structure and properties of alginate-based bioink, the 3D bioprinting processing parameters, and the implementation of resulted hydrogel scaffold and organoid.