Characterization of 3D printed biodegradable piezoelectric scaffolds for bone regeneration

Objective: The primary objective of this research was to develop a poly(l-lactic acid) (PLLA) scaffold and evaluate critical characteristics essential for its biologic use as a craniofacial implant. Materials and Methods: PLLA scaffolds were designed and fabricated using fused deposition modeling technology. The surface morphology and microarchitecture were analyzed using scanning electron microscopy (SEM) and microCT, respectively. Crystallography, compressive modulus, and the piezoelectric potential generated upon mechanical distortion were characterized. Hydrolytic degradation was studied. MG63 osteoblast-like cell proliferation and morphology were assessed. Results: The porosity of the scaffolds was 73%, with an average pore size of 450 µm and an average scaffold fiber thickness of 130 µm. The average compressive modulus was 244 MPa, and the scaffolds generated an electric potential of 25 mV upon cyclic/repeated loading. The crystallinity reduced from 27.5% to 13.9% during the 3D printing process. The hydrolytic degradation was minimal during a 12-week period. Osteoblast-like cells did not attach to the uncoated scaffold but attached well after coating the scaffold with fibrinogen. They then proliferated to cover the complete scaffold by Day 14. Conclusion: The PLLA scaffolds were designed and printed, proving the feasibility of 3D printing as a method of fabricating PLLA scaffolds. The elastic modulus was comparable to that of trabecular bone, and the piezoelectric properties of the PLLA were retained after 3D printing. The scaffolds were cytocompatible. These 3D-printed PLLA scaffolds showed promising properties akin to the natural bone, and they warrant further investigation for bone regeneration.