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

Abstract

In this study, hydroxyapatite (HAp) coated Mg matrix composites were fabricated for biodegradable implant applications. Spark plasma sintering was employed to fabricate the Mg-10 wt% ZnO composite substrates. HAp was coated on the surface of the sintered composites and pure Mg by a chemical solution treatment. SEM and optical micrographs of coated samples showed that HAp grew homogeneously and formed a layer on the entire surface of both pure sintered Mg and Mg composites. The immersion and polarization test results demonstrated that the HAp coating significantly improved the corrosion resistance of the sintered composites. While the HAp coating layer is not effective in the improvement of the pure Mg substrate, cell culture test results revealed that the HAp coating improved cell adhesion and proliferation on the composites effectively through 72 h, while no cell could survive on the uncoated composites after 72 h. In addition, the corrosion tests and cell culture test results indicated that the composite with longer sintering time has better corrosion resistance and cell viability than those of the composite with shorter sintering time. The findings suggested that the HAp-coated Mg-10 wt% ZnO-2.5 h + 10 min composite is a high-potential candidate for biodegradable implant applications.

In vitro biodegradation behavior of biodegradable hydroxyapatite coated AZ31 alloy treated at various pH values

“…The uniform-crystalline structure of the HA coating grown at pH 7.5 created a wall to protect the substrate from the solution. However, as reported previously 15,22 that there are always nano-pores existed in HA layer formed on the surface of Mg alloys. Therefore, the corrosion still occurred for this sample with a very low rate.…”

“…The formation of Mg(OH) 2 on the surface of sample coated at pH 10.5 was consistent with results of previous studies. 15,25 Cao et al and Lei et al reported that, at a high corrosion rate of Mg alloys, the corrosion product deposited on the surface of the sample was mainly Mg(OH) 2 . This Mg(OH) 2 layer has porous structure as shown.…”

Mechanical Properties and Corrosion Resistance of Magnesium–Hydroxyapatite Composites Fabricated by Spark Plasma Sintering

“…Also, surgery cost is expensive and the cost cannot be ignored. To address these two points, magnesium and its alloys are widely mentioned as desirable materials for solving these problems [2,12,13]. The Young's modulus of cortical bone is known to be approximately 20 to 30 GPa.…”

“…The results indicated that the effects of the preparation method on the mechanical properties of Mg-HAP composites were even stronger than the volume fraction of reinforcement. Cao et al [13] coated Mg matrix composites with a HAP layer using a chemical solution treatment. They tested the in vitro corrosion behavior and cell response by immersion, polarization test, and cell culture tests.…”

“…Hanks' solution is often used for analyzing and simulating the corrosion properties of metallic biomaterials in a human body since it is composed of inorganic salts and supplemented with glucose [13,24,25]. For the application of an orthopedic implant, this solution is one of the best solutions for investigating the corrosion properties as an in-vitro test comparing with other solutions.…”