Experimental and numerical characterization of 3D-printed scaffolds under monotonic compression with the aid of micro-CT volume reconstruction

Even when damaged by injury or disease bone tissue has the remarkable ability to regenerate. When this process is limited by large size bone defects, tissue engineering is responsible for restoring, maintaining or improving tissue function. Scaffolds are support structures, designed to be implanted in the damaged site, supporting mechanical loads and protecting the regenerating bone tissue. In this paper, 3D-printed PLA scaffolds with three different porosity values and two different geometries were experimentally and numerically characterized. Micro-CT analysis showed that fused filament fabrication can be used to produce scaffolds with the desired porosity and 100% of interconnected pores. Under monotonical compression, scaffolds apparent compressive modulus increased from 89 to 918 MPa, while yield stress increased from 2.9 to 27.5 MPa as porosity decreased from 70 to 30%. Open porosity decreased up to 8% on aligned scaffolds and 14% on staggered scaffolds, after compression, while scaffold's surface-to-volume ratio highest reduction (7.48 to 4.55 mm(-1)) was obtained with aligned low porosity scaffolds. Micro-CT volume reconstruction allowed for scaffold simplified numerical models to be built and analyzed. Excellent agreement was found when predicting scaffold's apparent compressive modulus. Overall, it can be concluded that 3D printing is a viable scaffold manufacturing technique for trabecular bone replacement.

Automated summary

This study experimentally and numerically characterized 3D-printed PLA scaffolds with different porosity values and geometries, demonstrating a correlation between compressive modulus and open porosity with porosity and geometry. The use of fused filament fabrication was shown to produce scaffolds with desired porosity and interconnected pores, confirming its viability as a manufacturing technique for trabecular bone replacement.