3D-Printing of Hierarchically Designed and Osteoconductive Bone Tissue Engineering Scaffolds

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Orthopedic Surgery

Background:

• Autologous bone-regenerative cells and scaffolds are used in Bone Tissue Engineering (BTE) for large bone defect treatment (LBDT).
• Existing polylactic acid (PLA) scaffolds successful in small animals face challenges in large animal models due to diffusion limitations impacting cell survival.
• Increased diffusion distances in scaled-up scaffolds lead to cell death and implant failure.

Purpose of the Study:

• To design and evaluate a novel scaffold architecture for advanced bone substitutes in LBDT.
• To overcome limitations of existing scaffolds by optimizing nutrient and oxygen supply to inner implant regions.
• To assess the biocompatibility and osteogenic potential of the new scaffold design.

Main Methods:

• A novel biofunctional, porous subunit scaffold within a load-bearing frame was designed.
• The scaffold featured an open, macro- and microporous internal architecture (100 µm-2 mm pores).
• A prototype was 3D-printed using Fused Filament Fabrication with PLA and incubated with Saos-2 cells for 14 days.

Main Results:

• Cell morphology, distribution, survival, and metabolic activity were assessed.
• Fluorescence microscopy and cytotoxicity assays confirmed cell survival and proliferation.
• MTT tests and gene expression analysis indicated osteogenic differentiation of adherent cells.

Conclusions:

• The innovative scaffold design demonstrates excellent cell settlement, proliferation, and osteogenic differentiation.
• The porous structure effectively optimizes oxygen and nutrient supply, crucial for cell viability.
• The modular design facilitates upscaling and presents a viable solution for large bone defect treatment.