Tuning PLLA Scaffold Crystal Structure via Epitaxial Crystallization for Enhanced Osteoblast Compatibility

ABSTRACT This study employed two‐step epitaxial crystallization to fabricate PLLA double‐filament scaffolds with tailored properties and enhanced biocompatibility. Heterogeneous nucleation markedly elevated crystallinity, wherein total duration governed overall crystallinity and stepwise timing dictated crystal quality. A short–long regime preferentially yielded higher‐quality α‐crystals over the long–short approach. Epitaxial crystallization refined α‐grain size under fixed total time, with initial duration being pivotal: prolonged steps favored β‐crystals, whereas abbreviated ones promoted α‐nucleation. Extended crystallization facilitated α‐spherulite formation, while shorter durations produced mixed morphologies. Epitaxy enhanced hydrophobicity; conversely, dual short steps generated high‐density fine grains, defects, and elevated surface energy. Biocompatibility assessments revealed favorable L‐P scaffold adaptation via moderate 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine (POPC) interactions. After co‐culture with NIH‐3T3 fibroblasts, L‐L and L‐P scaffolds subjected to dual short‐step crystallization achieved proliferation rates of 159% and 200%, respectively; the latter also supported more uniform MC‐3T3‐E1 pre‐osteoblast distribution. These results underscore two‐step epitaxial crystallization as a promising strategy for customizing PLLA scaffolds, providing valuable insights for developing advanced biomaterials in tissue engineering.