Porous polycaprolactone scaffold for cardiac tissue engineering fabricated by selective laser sintering

An advanced manufacturing technique, selective laser sintering (SLS), was utilized to fabricate a porous polycaprolactone (PCL) scaffold designed with an automated algorithm in a parametric library system named the “computer-aided system for tissue scaffolds” (CASTS). Tensile stiffness of the sintered PCL strut was in the range of 0.43 ± 0.15 MPa when a laser power of 3 W and scanning speed of 150 in s−1 was used. A series of compressive mechanical characterizations was performed on the parametric scaffold design and an empirical formula was presented to predict the compressive stiffness of the scaffold as a function of total porosity. In this work, the porosity of the scaffold was selected to be 85%, with micropores (40–100 μm) throughout the scaffold. The compressive stiffness of the scaffold was 345 kPa. The feasibility of using the scaffold for cardiac tissue engineering was investigated by culturing C2C12 myoblast cells in vitro for 21 days. Fluorescence images showed cells were located throughout the scaffold. High density of cells at 1.2 × 106 cells ml−1 was recorded after 4 days of culture. Fusion and differentiation of C2C12 were observed as early as 6 days in vitro and was confirmed with myosin heavy chain immunostaining after 11 days of cell culture. A steady population of cells was then maintained throughout 21 days of culturing. This work demonstrated the feasibility of tailoring the mechanical property of the scaffold for soft tissue engineering using CASTS and SLS. The macroarchitecture of the scaffold can be modified efficiently to fabricate scaffolds with different macropore sizes or changing the elemental cell design in CASTS. Further process and design optimization could be carried out in the future to fabricate scaffolds that match the tensile strength of native myocardium, which is of the order of tens of kPa.