3D bioprinting of functional cell-laden bioinks and its application for cell-alignment and maturation

Abstract Biomedical scaffolds should provide physical, biological, and topographical cues to seeded or laden cells to successfully mimic the physiochemical properties of native tissues. Cell-laden scaffolds, in particular, can efficiently deliver various cells safely to the defected region. However, the fabrication of a functional cell-laden structure with a topographical cue has been an overcoming issue. In this study, we used a GelMa-based hydrogel, which is used as a bioink in various cell-embedding systems, to fabricate a functional bioink to easily and efficiently induce topographical cue by wall shear stress within an extruding nozzle of the 3D printing system. The functional bioink was obtained by pre-culturing the cell-laden bioink. The pre-culturing periods were optimized to develop an anisotropic morphological shaped cell/cytoskeleton, which is more sensitive to the external shear stress in comparison to the spherical morphological shaped laden cells. In vitro cellular activities with C2C12 myoblasts showed that the pre-cultured cell-laden GelMa bioink with non-spherical morphological shaped cell/cytoskeleton was fully aligned to the printing direction and showed outstanding results for the myotube alignment and maturation, as compared to the general cell-laden bioink. To show the feasibility of the method, we used a ColMa (methacrylated collagen)-based bioink and successfully obtained fully aligned myotubes in the cell-laden ColMa-structure. Furthermore, hASCs (human adipose stem cells) and hMPCs (muscle precursor cells) were applied in this method, and the cells were fully aligned in a printing direction. The in vitro results suggest that the new method has great potential for attaining aligned tissue structures, providing a unique topographical cue to the laden cells.