Homogeneous cell printing on porous PCL/F127 tissue engineering scaffolds

In tissue engineering, cell-laden scaffold has gradually replaced cell-less scaffold due to better biological performance. However, manual pipetting, the traditional cell seeding for cell-laden scaffold, leads to an imprecise and inhomogeneous cell distribution. As an alternative, micro-extrusion of cell-laden hydrogel achieves homogenous cell distribution, but causes high shear stress which is harmful to cells. To address this challenge, the objective of this study is to print cells on porous scaffold precisely without causing high shear stress to produce homogeneous cell-laden hybrid scaffold. Porous polycaprolactone scaffold fabricated through electro-hydrodynamic jetting was used as a representation. To improve scaffold hydrophilicity for better cell adhesion, 6% (w/w) Pluronic F127 was blended with polycaprolactone. HeLa cells, as a demonstration, were ejected on the scaffold fibers through piezoelectric inkjet printing. As a result, inkjet printing showed a more precise and homogeneous cell distribution and enhanced cell proliferation compared to manual pipetting (1.34- fold increase after 7 days). Furthermore, due to the low viscosity of cell solution, the average shear stress caused during inkjet printing was 1.79 kPa as opposed to 18 kPa of micro-extrusion, which is friendly to cells. In summary, through inkjet printing, homogeneous cell-laden hybrid scaffold could be fabricated with lower shear stress.