Simulation of biodegradable behaviour of magnesium wire/polylactic acid composite for bone fracture healing under human body environment

Abstract

This study was aimed at developing a technique for simulating the material degradation of a biodegradable composite comprising magnesium wires as reinforcement and polylactic acid as the matrix using a phosphate-buffered saline (PBS) solution in a simulated human body environment. For accurate simulation, parameters like the diffusion coefficients of each component of the composite were considered by referring to previous researches on degradation experiments of magnesium alloy and PLA in human body environment. The chemical reaction with the PBS solution and material dissolution were also simulated, utilising element deletion under the appropriate criteria. The PBS uptake rate and changes in mechanical properties were estimated by finite-element analysis, and the diffusion coefficients for each component were calibrated using experimentally acquired data, such as the PBS uptake rate of the composite specimen. A bone plate with screw holes for fastening fractured bones was simulated, and the degradation in material and mechanical properties was estimated to assess the serviceability, such as the load-carrying capacity, of the biodegradable composite as prostheses.