Accelerated degradation mechanism and mechanical behavior of 3D-printed PLA scaffolds for bone regeneration

A correct understanding of the process of scaffold degradation can help a proper scaffold design of bone regeneration. Polylactide acid (PLA) scaffolds are a suitable alternative for bone regenerations due to their mechanical and biodegradable properties, but their degradation tests are time-consuming and costly. Using reliable accelerated methods for in vitro experiments to save time and cost and give valid test results for scaffold degradation can be critical. In this study, two kinds of scaffolds with 60% and 80% porosities have been fabricated using the fused deposition modeling (FDM) technique. The accelerated degradation method was investigated using an alkaline solution of 0.074 M NaOH at 37 degrees C with pH 12.5, and the results were analyzed. The degradation of PLA scaffolds subjected to hydrolysis was evaluated based on changes in weight loss, molecular weight distribution, mechanical properties, crystallinity, and morphological analyses, for a 50 day time interval. It was found that changes in the scaffolds' porosity greatly influence weight loss, molecular weight loss, and decrease in mechanical properties. A 20% increase in porosity leads to 2.6% more weight loss and 2% greater average molecular weight loss. Rapid yield stress reduction was observed in both porosities. Elastic modulus had a 91% reduction in 80% and a 42% reduction in 60% porosity scaffolds. The morphological changes are more evident in porosity of 80% with surface erosion in both scaffolds. The 60% porosity scaffolds showed better mechanical properties and integrity until the end of the test.