Characterization And Biocompatibility Of A Novel Bioink Of Collagen And Hydroxyapatite
3D bioprinting is an additive manufacturing process that incorporates viable cells into a three-dimensional matrix. The objectives of this study are to characterize a novel matrix of collagen and hydroxyapatite and to assess the effects of the 3D bioprinting process on cytotoxicity, proliferation rate, and cytokine expression of HEPM (Homo sapiens palatal mesenchyme) cells. We prepared 3D constructs of collagen and hydroxyapatite without and with cells from a novel bioink formulation. We used histology, SEM and TEM to characterize the structure and arrangement of the collagen fibers. We then incubated the 3D constructs with known standards of cytokines to measure adsorption. Finally, we assessed the cytotoxicity of this matrix for HEPM cells and assessed its effect on the production of chemokines and cytokines. A one-way fixed effect ANOVA was fit to concentrations of cytokines and pairwise group comparisons were conducted using Tukey's Honest Significant Differences test (p<0.05). The matrix was found to contain strands of collagen and some hydroxyapatite crystals that did not absorb any of the cytokines measured except for MIP-1a (p< 0.05). The matrix was found to be non-cytotoxic using an Alamar Blue® assay. In the presence of the hydrogel the HEPM cells had similar expression profiles of the cytokines measured (P > 0.05 for GMCSF, IL-6, IL-8, and RANTES). Here we show that a novel matrix of collagen and hydroxyapatite is non-cytotoxic to HEPM cells and the 3D bioprinting process does not induce a proinflammatory response.