Cell-Laden Thermosensitive Chitosan Hydrogel Bioinks for 3D Bioprinting Applications

Three-dimensional (3D) bioprinting is a technology used to deposit cell-laden biomaterials for the construction of complex tissues. Thermosensitive hydrogels are physically cross-linked by non-covalent interaction without using crosslinkers, facilitating low cytotoxicity and cell viability. Chitosan, which is a non-toxic, biocompatible and biodegradable polysaccharide, can be used as a thermosensitive hydrogel. Therefore, chitosan hydrogel could be of potential use as a 3D bioprinting ink. The purpose of this study was to develop and compare the effectivity of different bioinks based on chitosan hydrogels for 3D bioprinting. The solvent type did not affect the gel shape and gelation time, whereas acetic acid exhibited better biocompatibility compared to lactic and hydrochloric acids. The nature of the gelling agent was found to have a stronger influence on these characteristics than that of the solvent. The NaHCO3 moiety exhibited a higher growth rate of the storage modulus (G′) and a more irregular porous structure than that of the β-glycerophosphate (β-GP) and K2HPO4 groups. Cell viability, and live and dead assays, showed that the NaHCO3 group was more efficient for cell adhesion. The type of gelling agent did not lead to appreciable differences in cell-laden constructs. The NaHCO3 group was more amenable to bioprinting, compared to the β-GP and K2HPO4 groups. The chitosan hydrogel bioinks could, therefore, be good candidates for 3D bioprinting and would pave the way for patient-specific regenerative medicines.