Scaffold fabrication by indirect three-dimensional printing.

Three-dimensional printing (3DP) has been employed to fabricate porous scaffolds by inkjet printing liquid binder droplets onto particulate matter. Direct 3DP, where the final scaffold materials are utilized during the actual 3DP process, imposes several limitations on the final scaffold structure. This study describes an indirect 3DP protocol, where molds are printed and the final materials are cast into the mold cavity to overcome the limitations of the direct technique. To evaluate the resolution available in this technique, scaffolds with villi features (500 microm diameter, 1 mm height) were produced by solvent casting into plaster molds, followed by particulate leaching. Scanning electron microscope (SEM) showed highly open, well interconnected, uniform pore architecture ( approximately 100-150 microm). The ability of these scaffolds to support intestinal epithelial cell (IEC6) culture was investigated in vitro. IEC6 cells attached to scaffolds uniformly in vitro and grew preferentially in the villi region. To exploit the freeform nature of this technique with large pore size, anatomically shaped zygoma scaffolds with 300-500 microm interconnected pores were produced and characterized. Indirect 3DP provides an alternative method to complement other direct solid freeform fabrication methods.