Assessment of 3D Printed PEG-PCL/nHA Composite Scaffolds for Bone Regeneration

Although bone tissue possesses inherent regenerative capabilities, bone defects exceeding the critical size remain a significant challenge for successful healing. Consequently, developing biodegradable scaffolds with desirable mechanical and biological properties offers a promising alternative to promote bone regeneration. In this study, porous scaffolds composed of a ternary composite based on polyethylene glycol (PEG), polycaprolactone (PCL), and nanohydroxyapatite (nHA) were successfully fabricated for bone tissue engineering using 3D printing technology. The physicochemical properties of the 3D-printed PEG-PCL/nHA scaffolds were systematically investigated. Results demonstrated that increasing the PEG content to 20% significantly enhanced scaffold hydrophilicity, reducing the water contact angle from 80.01 ± 0.51° to 62.46 ± 2.39° (P < 0.001), while porosity increased from 44.37 ± 1.68% to 57.21 ± 1.55% (P < 0.05). However, the elastic modulus decreased from 93.93 ± 7.16 MPa to 51.56 ± 2.46 MPa, and compressive strength declined from 7.87 ± 0.43 MPa to 3.69 ± 0.26 MPa (both P < 0.05). In vitro degradation studies revealed a mass loss of 36.98 ± 0.75% for the 20% PEG-PCL/nHA scaffold after 12 weeks, significantly higher than the 10.5 ± 0.14% observed for PCL/nHA controls (P < 0.001). MC3T3-E1 cells were used to analyze cytocompatibility and osteogenic performance. CCK-8 assays confirmed noncytotoxicity, with cell viability reaching 92.5 ± 0.36% on 20% PEG-PCL/nHA scaffolds. Cells exhibited well-spread morphology and superior adhesion on PEG-modified surfaces. Notably, the 20% PEG-PCL/nHA scaffold promoted osteogenic differentiation, showing a significant increase in alkaline phosphatase (ALP) activity and upregulation of osteogenesis-related genes (Runx2 and Col1a1). Thus, among the compositions tested in this study, the 20% PEG-PCL/nHA composite provided a favorable balance of enhanced hydrophilicity, porosity, degradation rate, and osteogenic activity, albeit with a reduction in mechanical strength. These results suggest its promising potential as a scaffold material for bone tissue engineering.