Biomimetic 2D-oriented microporous PLLA scaffolds: Fabrication and evaluation for bone repair

Poly(_L-lactic) acid (PLLA) was limited in the application of bone repair materials due to its brittleness, poor melt strength and poor cellular affinity. In this work, single epoxy-terminated polydimethylsiloxane (e-PDMS) was used to extend the molecular chain of PLLA and improve the melt strength of PLLA. Subsequently, a uniform two-dimensional(2D) oriented microporous biomimetic structure was constructed by combining the biaxial orientation technology with the supercritical carbon dioxide (SC-CO₂) foaming technology, which greatly improved the strength and toughness of PLLA (from 54.9 MPa,7.3 % to 133.6 MPa,72.6 %). This 2D oriented microporous PLLA was also more conducive to the expression of anti-inflammatory factors and pro-inflammatory factors simultaneously in mouse bone marrow macrophages (iBMDM), which had an effect on regulating inflammation. At the same time, this structure was also helpful to the adhesion and growth of mouse embryonic fibroblasts (NIH-3 T3), and can stimulate the activity of mouse embryonic osteoblast precursor cells (MC-3 T3-E1), showing good biocompatibility.