PPDO-induced tunable degradation and HA-enhanced osteogenesis in PLCL scaffolds for bone regeneration

Poly(lacticacid-ε-caprolactone) (PLCL) scaffolds face significant challenges in bone regeneration due to excessively slow degradation kinetics and inherent hydrophobicity. To overcome these limitations, we developed a novel ternary 3D-printed scaffold composed of PLCL, poly(p-dioxanone) (PPDO), and hydroxyapatite (HA) <i>via</i> fused deposition modeling (FDM) for the first time. The incorporation of PPDO would accelerate and enable tunable degradation of PLCL to match the bone healing timeline, while HA was aimed to enhance osteoinductivity and regulated the pH level to reduce adverse immune reactions of the acidic degradation products. The results demonstrated that degradation rate of the scaffolds was found to be modulated by PPDO and HA effectively. Moreover, the 3D printing extrusion enabled the porous scaffolds with customizability, diverse shapes, adjustable porosity and uniform pore sizes. In addition, proliferation and adhesion of bone marrow mesenchymal stem cells (BMSCs) as well as the expression of various osteogenic genes (ALP, Col-Ι, OCN, BMP-2, OPN) were also upregulated on the PLCL/PPDO/HA scaffolds. Therefore, these low-cost 3D-printed scaffolds may serve as an optimal bone graft for applications in bone tissue engineering.