Modelling the degradation and elastic properties of poly(lactic-co-glycolic acid) films and regular open-cell tissue engineering scaffolds. (February 2016)

• Record Type: Journal Article
• Authors: Shirazi, Reyhaneh Neghabat; Ronan, William; Rochev, Yury; McHugh, Peter
• Is Part Of: Journal of the mechanical behavior of biomedical materials. Volume 54(2016)
• Page Start: 48
• Page End: 59
• Publication Date: 2016-02
• Subjects: PLGA -- Degradation -- Finite element modelling -- Tissue engineering scaffold -- Mechanical properties -- Size effect; Biomedical materials -- Periodicals; Biomedical materials -- Mechanical properties -- Periodicals; Biomedical materials; Biomedical materials -- Mechanical properties; Periodicals; Electronic journals; 610.28
• DOI: 10.1016/j.jmbbm.2015.08.030
• Languages: English
• ISSNs: 1751-6161

Abstract

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 2–100 μm. Below this range, slower homogenous degradation occurs; however, for larger samples monomers are trapped inside the sample and faster autocatalytic degradation occurs. Graphical abstract: Highlights: A coupled molecular weight degradation and mechanical properties model is developed The coupled model captures the experimentally observed degradation of PLGA films Degradation is shown to be homogenous or autocatalytic depending on scaffold size Autocatalysis is caused by diffusion-limited build-up of monomers inside scaffolds