Biodegradation, mechanical and biocompatibility evaluation of compact and porous polylactic acid after long-term dynamic fluid immersion

BACKGROUND

Polylactic acid (PLA) is the most widely used thermoplastic in applications in the benefit of humans, such as biomedicine and food packaging. However, its behaviour when operating in relevant environments has not been fully investigated. In this research, the effect of the long-term interaction between biocompatible PLA and a physiological fluid was monitored.

RESULTS

The weight variation of the samples, as well as their micro- and nanomechanical properties, were evaluated during PLA immersion until dissolution. Scanning electron micrographs indicated degradation of the PLA layer line from Day (D)3 onwards. More pronounced damage involved plasticization and breakage was noted after D14. The weight of the samples started to decrease considerably after the first month of immersion. Scaffolds were dissolved after D70 of immersion. The microscopic compression modulus decreased from 100 to 45 MPa within 42 days of immersion. Nanoindentation testing indicated important degradation of surface properties (stiffness and hardness) by D70 after immersion, especially in the case of higher loading forces of 3000 μΝ. Biomarker analysis of stem cells deposited on the substrates revealed a correlation between material degradation profile and biomarkers variations.

CONCLUSIONS

The biodegradation rate and the mechanical performance of both compact and porous samples were investigated after their immersion in cell culture medium, which closely mimics the body fluid composition, in a dynamic environment involving stirring conditions and body temperature. A correlation was found between the degradation of properties at the microscale with nanoscale events and stem cell feedback. © 2025 The Author(s). Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).