High-performance porous PLLA-based scaffolds for bone tissue engineering: Preparation, characterization, and in vitro and in vivo evaluation

Porous poly (L-lactic acid) (PLLA)-based tissue engineering scaffolds have gained growing interests due to their unique structures and properties. However, the simple and green fabrication of PLLA-based scaffolds with uniform and interconnected pore structure, good degradability and hydrophobicity, and excellent biocompatibility remain a major challenge. Herein, we developed a facile, cost-effective and eco-friendly structural manipulation processing with supercritical carbon dioxide (Sc-CO₂) foaming technique to prepare porous PLLA/poly (ethylene glycol) (PEG) (95/5 wt%) scaffolds. First, structural manipulation processing was used to manipulate the formation of oriented crystal structure in a PLLA matrix, which could slow down the gas escaping during the Sc-CO₂ foaming process. Subsequently, the Sc-CO₂ foaming process was utilized to form 3D porous scaffolds, which are suitable for the cell growth, migration and proliferation. The fabricated porous biodegradable scaffold exhibited high porosity (90.3%), uniform and interconnected open-pores, good strengths (11.9 MPa/(g·cm³)), degradabilities and hydrophilicities (75.7 ± 2.1°), as well as excellent in vitro biocompatibilities. For in vivo application, a rabbit model with bone defects was utilized, and both the histological analysis and immunohistochemical analysis results revealed that the obtained porous PLLA/PEG scaffolds support bone tissue engineering.