Preparation of three-dimensional scaffolds by using solid freeform fabrication and feasibility study of the scaffolds

To adapt biomaterials for solid freeform fabrication (SFF), methoxy polyethylene glycol (MPEG)-(PLLA-co-PCL) (L_xC_y) block copolymers were prepared using MPEG as the initiator to precisely control the molecular weight of PLLA and PCL. The L_xC_y block copolymers were designed such that the PLLA and PCL content varied and their molecular weights were within 200-1000 kDa. The cylindrical L_xC_y scaffolds were prepared by using L_xC_y block copolymers in SFF. The feasibility of using L_xC_y block copolymers was examined in terms of flowability from the micronozzle and solidification at room temperature after scaffold printing. The flowability and solidification of L_xC_y block copolymers mainly depend on the proportions of PLLA and PCL. Fabrication of the cylindrical L_xC_y scaffolds by using SFF was rapid and showed high reproducibility. In in vivo implantation, the cylindrical L_xC_y scaffolds exhibited biocompatibility and gradual biodegradation on a 16 week timescale. Immunohistochemical characterization showed that the in vivo L_xC_y scaffolds elicit only a modest inflammatory response. Taken together, these results show that L_xC_y block copolymers may serve as suitable biomaterials for the fabrication of well-defined three-dimensional scaffolds by using SFF.