Degradation behaviors and cytocompatibility of Mg/β‐tricalcium phosphate composites produced by spark plasma sintering

Abstract

Magnesium (Mg)‐based materials have shown great potentials for bioresorbable implant applications. Previous studies showed that Mg with 10 and 20 vol % β‐tricalcium phosphate (β‐TCP) composites produced by spark plasma sintering, improved mechanical properties when compared with pure Mg. The objectives of this study were to evaluate the degradation behaviors of Mg/10% β‐TCP and Mg/20% β‐TCP composites in revised stimulated body fluid (rSBF), and to determine their cytocompatibility with bone marrow derived mesenchymal stem cells (BMSCs) using the direct culture method. During the 11 days of immersion in rSBF, Mg/β‐TCP composites showed different degradation behaviors at different immersion periods, that is, the initial stage (0–1 hr), the mid‐term stage (1 hr to 2 days), and the long‐term stage (2−11 days). The counter effects of mass loss due to microgalvanic corrosion and mass gain due to deposition of Ca‐P containing layers resulted in slower Mg2+ ion release for Mg/20% β‐TCP than Mg/10% β‐TCP in the mid‐term, but eventually 16% mass loss for Mg/20% β‐TCP and 10% mass loss for Mg/10% β‐TCP after 11 days of immersion. The in vitro studies with BMSCs showed the highest cell adhesion density (i.e., 68% of seeding density) on the plate surrounding the Mg/10% β‐TCP sample, that is, under the indirect contact condition of direct culture. The β‐TCP showed a positive effect on direct adhesion of BMSCs on the surface of Mg/β‐TCP composites. This study elucidated the degradation behaviors and the cytocompatibility of Mg/β‐TCP composites in vitro; and, further studies on Mg/ceramic composites are needed to determine their potential for clinical applications. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2238–2253, 2019.

In Vitro Corrosion and Cell Response of Hydroxyapatite Coated Mg Matrix in Situ Composites for Biodegradable Material Applications

“…The results demonstrated that HA effectively reinforced the mechanical properties and improved corrosion resistance of the fabricated composite compared to those of the AZ91 alloy [9]. Narita et al fabricated Mg/β-TCP composites via the spark plasma sintering method for biodegradable material applications [10]. The findings indicated that the in vitro corrosion resistance and cytocompatibility of the fabricated Mg/β-TCP composites have been enhanced effectively compared to those of pure Mg.…”

Effects of Incorporating Β-Tricalcium Phosphate with Reaction Sintering into Mg-Based Composites on Degradation and Mechanical Integrity

“…The total area of RPs in the Mg/20% β-TCP was larger than that in the Mg/10% β-TCP. Figure 1D,E show scanning electron microscope (SEM) images and the corresponding energy dispersive spectroscopy (EDS) analysis (reproduced from our previous study [34]). The results show that Ca was diffused to the adjacent area of the Mg matrix to the RPs area.…”

“…The results show that Ca was diffused to the adjacent area of the Mg matrix to the RPs area. The detection of carbon was attributed to adventitious carbon contamination and diffusion from a carbon die used in the SPS process [34]. The formed RPs were characterized by XRD as shown in Figure 2.…”

“…Without the reactions, the Mg/β-TCP composites showed lower strength than sintered Mg because β-TCP did not act as reinforcement due to insufficient interfacial bonding between β-TCP and Mg for load transfer, as other Mg/bioceramic composites showed deteriorated strength [12,22,23]. We also conducted in vitro degradation tests using revised simulated body fluid and cytocompatibility tests on the developed Mg/β-TCP composites [34]. Among the tested samples, sintered Mg, Mg/10% β-TCP, and Mg/20% β-TCP, Mg/10% β-TCP showed the slowest Mg 2+ ion release rate after the immersion for 11 days as a result of the counter-effects between microgalvanic corrosion and deposition of Ca-P containing degradation layers, both of which occurred due to the existence of the unique microstructure evolved by the reactions between Mg and β-TCP [34].…”

“…We also conducted in vitro degradation tests using revised simulated body fluid and cytocompatibility tests on the developed Mg/β-TCP composites [34]. Among the tested samples, sintered Mg, Mg/10% β-TCP, and Mg/20% β-TCP, Mg/10% β-TCP showed the slowest Mg 2+ ion release rate after the immersion for 11 days as a result of the counter-effects between microgalvanic corrosion and deposition of Ca-P containing degradation layers, both of which occurred due to the existence of the unique microstructure evolved by the reactions between Mg and β-TCP [34].…”