title: Modelling the degradation and elastic properties of poly(lactic-co-glycolic acid) films and regular open-cell tissue engineering scaffolds.
abstract: Scaffolding plays a critical rule in tissue engineering and an appropriate degradation rate and sufficient mechanical integrity are required during degradation and healing of tissue. This paper presents a computational investigation of the molecular weight degradation and the mechanical performance of poly(lactic-co-glycolic acid) (PLGA) films and tissue engineering scaffolds. A reaction-diffusion model which predicts the degradation behaviour is coupled with an entropy-based mechanical model which relates Young׳s modulus and the molecular weight. The model parameters are determined based on experimental data for in-vitro degradation of a PLGA film. Microstructural models of three different scaffold architectures are used to investigate the degradation and mechanical behaviour of each scaffold. Although the architecture of the scaffold does not have a significant influence on the degradation rate, it determines the initial stiffness of the scaffold. It is revealed that the size of the scaffold strut controls the degradation rate and the mechanical collapse. A critical length scale due to competition between diffusion of degradation products and autocatalytic degradation is determined to be in the range 2-100μm. Below this range, slower homogenous degradation occurs; however, for larger samples monomers are trapped inside the sample and faster autocatalytic degradation occurs.
authors.affiliation: Biomechanics Research Centre (BMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Ireland. Electronic address: r.neghabatshirazi1@nuigalway.ie.
authors.forename: Reyhaneh Neghabat
authors.initials: RN
authors.lastname: Shirazi
authors.affiliation: Biomechanics Research Centre (BMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Ireland.
authors.forename: William
authors.initials: W
authors.lastname: Ronan
authors.affiliation: School of Chemistry, National University of Ireland Galway, Ireland; National Centre for Biomedical Engineering Science (NCBES), National University of Ireland Galway, Ireland.
authors.forename: Yury
authors.initials: Y
authors.lastname: Rochev
authors.affiliation: Biomechanics Research Centre (BMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Ireland.
authors.forename: Peter
authors.initials: P
authors.lastname: McHugh
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D055119:Elastic Modulus; D019344:Lactic Acid / Q000737:chemistry*; D008422:Materials Testing; D008958:Models, Molecular; D008968:Molecular Conformation; D008970:Molecular Weight; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid
keywords: Degradation; Finite element modelling; Mechanical properties; PLGA; Size effect; Tissue engineering scaffold