Construction of Chi(Zn/BMP2)/HA composite coating on AZ31B magnesium alloy surface to improve the corrosion resistance and biocompatibility

Abstract

As biodegradable orthopedic implant materials, magnesium alloys have been attracted enough attentions recently. However, too fast degradation in vivo, limited biocompatibilities, and insufficient antibacterial properties are three main challenges at present. In order to solve these problems, a multifunctional composite coating of Chi(Zn/BMP2)/HA was constructed on AZ31B magnesium alloy surface, successively by the alkali heating treatment, self-assembly of 16-phosphonyl-hexadecanoic acid, in situ immobilization of Chi(Zn/BMP2) (chitosan, zinc ions, and bone morphogenetic protein 2), and the deposition of HA (hydroxyapatite). The results of ATR-FTIR (attenuated total reflection Fourier transform infrared spectrum) spectra and elemental compositions confirmed that 16-phosphonyl-hexadecanoic acid, Chi(Zn/BMP2), and HA were successfully immobilized on the surface. Compared with Mg, Mg-OH, Mg-16, and Mg-Chi(Zn/BMP2), Mg-Chi(Zn/BMP2)/HA with the concave–convex structure surface significantly enhanced the hydrophilicity and corrosion resistance. On the other hand, Mg-Chi(Zn/BMP2)/HA coating also showed excellent biocompatibilities, which not only significantly promoted the osteoblast adhesion and proliferation, but also upregulated ALP and OCN expression of osteoblasts. Furthermore, due to the synergistic antibacterial effect of zinc ions and chitosan, Mg-Chi(Zn/BMP2)/HA showed a good antibacterial property against Escherichia coli (E. coli). Therefore, it can be said that the method used in this work has a good application prospect in improving the corrosion resistance, biocompatibility of magnesium alloys, and inhibiting infections against E. coli.

Epoxy Resin/(α-Al2O3/ZrO2) Nanocomposite for Antifriction and Corrosion Resistance

“…Particularly in medical applications, Mg alloys have bright prospects as medical devices owing to their high biocompatibility and biodegradability in human implants . In contrast to titanium-alloy orthopedic implants, which lack compatibility with natural bone tissue and inhibit bone growth, Mg alloys offer mechanical properties and biocompatibility similar to those of natural human bone. − This allows it to provide requisite bone support, reduce the “pressure-shielding effect,” and has bright prospects for application in medical equipment. − However, despite these advantages, the use of Mg alloys in medical devices and large-scale industrial applications is severely limited owing to their inadequate corrosion resistance and tribological properties. − Consequently, various methods have been developed to enhance the corrosion resistance and tribological properties of Mg alloys. For instance, Altun et al found through magnetron sputtering systems that depositing AlN coatings on different Mg alloys markedly enhanced their corrosion resistance compared to pure Mg-alloy substrates.…”

Topography Control of Micro-Nanosized Anatase Coating on Magnesium Alloy

“…For example, in bone fixation implants field, hydroxyapatite (HA), one of the primary constituents of bone, has been extensively prepared onto magnesium alloy substrates by different methods. In many cases, HA coatings could slow down the corrosion rate and improve the biocompatibility or osseointegration of magnesium alloy implants [9,10].…”