Effect of solution viscosity on retardation of cell sedimentation in DLP 3D printing of gelatin methacrylate/silk fibroin bioink

To improve the cell suspension of the gelatin-methacrylate(GelMA) bioink, the viscosity of the ink solution was controlled by biocompatible silk fibroin(SF) particles. The viscosity of the GelMA solution increased about 1.4 × 102 folds by the addition of 1 w/v% SF particles. The increase of solution viscosity reduced the displacement of cells and retarded the cell sedimentation significantly. SF-GelMA bioink containing 1 w/v% SF was non-cytotoxic and used for the 3D bioprinting by directly projecting a feature onto the bioink. The cells encapsulated in the structures showed a high level of metabolic activity and demonstrated that SF-GelMA was a biocompatible material.