Development of porous lamellar poly(L-lactic acid) scaffolds by conventional injection molding process

A novel fabrication technique is proposed for the preparation of unidirectionally oriented, porous scaffolds by selective polymer leaching from lamellar structures created by conventional injection molding. The proof of the concept is implemented using a 501 50 wt.% poly(L-lactic acid)/poly(ethylene oxide) (PLLA/PEO) blend. With this composition, the PLLA and PEO blend is biphasic, containing a homogeneous PLLA/PEO phase and a PEO-rich phase. The two phases were structured using injection moldinginto welldefined alternating layers of homogeneous PLLA/PEO phase and PEO-rich phase. Leaching of water-soluble PEO from the PEO-rich phase produces macropores, and leaching of phase-separated PEO from the initially homogeneous PLLA/PEO phase produces micropores in the lamellac. Thus, scaffolds with a macroporous lamellar architecture with microporous walls can be produced. The larnellae are continuous along the flow direction, and a continuous lamellar thickness of less than I mu m could be achieved. Porosities of 57-74% and pore sizes of around 50-100 mu m can be obtained using this process. The tensile elastic moduli of the porous constructs were between 580 and 800 MPa. We propose that this organic-solvent-free method of preparing lamellar scaffolds with good mechanical properties, and the reproducibility associated with the injection moldingtechnique, holds promise for a wide range of guided tissue engineering applications. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.