Ink comparison for extrusion-based bioprinting in the context of breast cancer and melanoma models
Biofabrication has proved to be a versatile and valuable tool for tissue engineering and cancer research in order to mimic different tumor microenvironments. In the present study, four different cell lines, including two melanoma cell lines, Mel Im and Mel Wei, and two breast cancer cell lines, MDA-MB-231 and MCF-7, were tested in combination with four hydrogels. The hydrogels were a composite ink consisting of alginate, hyaluronic acid and gelatine (Alg/HA/Gel), pre-crosslinked oxidized alginate with gelatine (ADA-GEL), alginate with methyl cellulose (Meth-Alg) and acrylated hyaluronic acid (HAA). Rheological analysis and shear stress calculations, printability assays and dynamic mechanical analysis were performed on all the hydrogels. The cell lines were then mixed into the hydrogels, printed and examined over a period of 14 days. The focus was on cell survival in the gel, metabolic activity and cell cycle analysis using FUCCI reporters. The results showed that all hydrogels were well printable and Meth-Alg was the softest gel. The cell lines survived the printing process in all inks, but there were significant differences in the metabolic activity and the predominant cell cycle stage. In Alg/HA/Gel, the cells grew in spheroid colonies. ADA-GEL proved to be a good bioink for all cell lines, which enabled proliferation, migration and supported the metabolic activity of the cells, while Meth-Alg offered pores for spreading and proliferating cells. However, it was shown that HAA resulted in the lowest cell number and metabolic activity for all cell lines due to its high polymer content, leading in senescence. Our data demonstrated that depending on the hypothesis, all inks are valuable approaches for breast cancer and melanoma models.