Effects of dynamic flow rates on degradation deposition behavior of Mg scaffold

Degradability of bone tissue engineering scaffold that matching the regeneration rate could allow a complete replacement of host tissue. However, the porous structure of biodegradable Mg scaffolds certainly generated high specific surface area, and the three-dimensional interconnected pores provided fast pervasive invasion entrance for the corrosive medium, rising concern of the structural integrity during the degradation. To clarify the structural evolution of the three-dimensional (3D) porous structure, semi-static immersion tests were carried out to evaluate the degradation performance in our previous study. Nevertheless, dynamic immersion tests mimicking the in vivo circulatory fluid through the interconnected porous structure have yet been investigated. Moreover, the effects of dynamic flow rates on the degradation deposition behavior of 3D porous Mg scaffolds were rarely reported. In this study, Mg scaffolds degraded at three flow rates exhibited different degradation rates and deposition process. A flow rate of 0.5 mL/min introduced maximum drop of porosity by accumulated deposition products. The deposition products provided limited protection against the degradation process at a flow rate of 1.0 mL/min. The three-dimensional interconnected porous structure of Mg scaffold degraded at 2.0 mL/min well retained after 14 days showing the best interconnectivity resistance to the degradation deposition process. The dynamic immersion tests disclosed the reason for the different degradation rates on account of flow rates, which may bring insight into understanding of varied in vivo degradation rates related to implantation sites.