Fabrication of graded macroporous poly(lactic acid) scaffold by a progressive solvent casting/porogen leaching approach

Biodegradable porous scaffolds play an important role as transplant vehicles for cultured cells or templates to guide tissue regeneration. Graded porous scaffolds can be utilized to study the interactions between cells or tissues and scaffolds with different pore sizes. In this study, a progressive solvent casting/porogen leaching (PSC/PL) approach was developed to fabricate a porous PLA scaffold with an axial pore size grade. The graded macroporous PLA scaffold was built up by solvent casting layer-by-layer progressively in a Buchner funnel with the assistance of a vacuum pump to facilitate the removal of solvent. The grade was achieved by gradually decreasing the size and content of salt at different layers. The resulting scaffold layers had an average thickness of 1 mm, a progressive pore size from 166 ± 41 μm to 453 ± 18 μm, and compressive moduli between 2.12 ± 0.08 MPa and 2.56 ± 0.18 MPa, which correspond to models of each layer (The compressive modulus of the whole graded macroporous PLA scaffold was 2.18 ± 0.24 MPa.). This method allows the fabrication of grade macroporous PLA scaffold in a simple, homogenous, and fast way.