Apatite-coated PLGA Scaffold Fabrication

Apatite-coated poly(lactic-coglycolic acid) (Ap-PLGA) scaffolds were prepared through solvent casting and particulate leaching processes following an established protocol as previously described.^{65 (link),66 (link)} Briefly, PLGA/CHCl₃ solution was mixed with sucrose (200–300 µm in diameter) to achieve a porosity of 92% (v/v), and the slurry was compressed into Teflon molds. After being lyophilized overnight, the scaffolds were immersed in Milli-Q water to leach out sucrose. The scaffolds were then sterilized in 70% EtOH for 30 min and rinsed with sterile water. Last, the scaffold sheets were shaped into round discs (3 mm in diameter and 0.5 mm in height) with a biopsy punch. The PLGA scaffolds were further coated with apatite layers by incubating scaffolds in simulated body fluid (SBF). The scaffold discs were subjected to glow discharge argon plasma etching (Harrick Scientific). The etched scaffolds were incubated in SBF1 composed of CaCl₂, MgCl₂•6H₂O, NaHCO₃, K₂HPO₄•3H₂O, Na₂SO₄, KCl and NaCl for 24 h and then further incubated in SBF2 composed of CaCl₂, K₂HPO₄•3H₂O, KCl and NaCl for another 24 h at 37 °C. The Ap-PLGA scaffolds were loaded with phosphate-buffered saline (PBS) or E2 (1, 5, 25 μmol·L^-1) and lyophilized for further usage.