Structural and Mechanical Durability Evaluation of PLLA Scaffolds for Biomedical Applications

Poly(L-lactide) (PLLA) scaffolds are widely used in tissue engineering because they are biodegradable and have good mechanical properties. Their performance changes during degradation, which is important for the design of biodegradable implants. In this study, we investigated the structural and mechanical stability of 3D-printed PLLA scaffolds during 180 days of in vitro hydrolytic degradation in phosphate-buffered saline (PBS) at 37 °C. Mechanical properties of the material were evaluated by tensile and compression tests. The material during degradation was analyzed for the scaffolds for which the lost mass and chemical and surface changes were analyzed using FTIR-ATR spectroscopy and SEM microscopy. The scaffolds lost more than 8% of their initial mass throughout the study, indicating slow degradation. However, their mechanical properties gradually decreased. Young's modulus dropped from 2.46 GPa to 2.09 GPa, and tensile strength decreased from 45.5 MPa to 31.1 MPa. The material also became more brittle after about 90 days. FTIR results confirmed progressive hydrolysis of ester bonds, while SEM images showed increasing surface roughness, micropores, and cracks. The results show that PLLA scaffolds maintain their shape and mass during the early stages of degradation. However, their mechanical strength decreases over time. These changes should be considered when designing biodegradable scaffolds for regenerative medicine.