Mg-Ca0.3 Electrochemical Activity Exposed to Hank’s Physiological Solution and Properties of Ag-Nano-Particles Deposits

Abstract

This work compares the degradation of Mg and Mg-Ca0.3 alloy when they are exposed for 14 days to Hank’s solution at 37 °C. A combination of immersion test, electrochemical techniques (PDP, EIS, EN), and surface characterization methods (SEM-EDS, XRD, and XPS) were carried out. The pH change over time, the lower mass loss (≈20%), and the lower concentration of the released Mg2+ ions (≈3.6 times), as well as the lower level of the surface degradation, allowed to consider the positive effect of Ca, presenting Mg-Ca0.3 alloy with lower electrochemical activity than that of Mg. The positive effect of Ca may be due to the formed layer characteristics on the alloy surface, which impedes the cathodic hydrogen evolution and Mg-ions release. The electroless deposited Ag-nano-particles (Ag-NPs) on Mg-Ca0.3 surface were characterized by SEM-EDS, XRD, UV-Vis, and contact angle. The agar-diffusion test was used to compare the growth of Staphylococcus aureus and Escherichia coli bacteria on Mg-Ca0.3 in the presence of Ag-NPs deposits in different size. Zeta-potential of the bacteria was negative, with respect to pH of the Mueller-Hinton culture broth. The greater antibacterial effect of S. aureus was attributed to its more negative zeta-potential, attracting more released Ag+ ions.

Electroless Deposits of ZnO and Hybrid ZnO/Ag Nanoparticles on Mg-Ca0.3 Alloy Surface: Multiscale Characterization

“…, Appendix A), electroless deposited on ZnO/Mg-Ca0.3, are observed at 2θ values of 38.18 • , 44.25 • , 64.72 • and 77.46 • , indexed for diffractions from the (111), (200), (220) and (311) planes, corresponding to the presence of Ag crystals of FCC cell structure (JCPDS No.04-0783). In our previous work, the Ag nanoparticles electroless deposited on Mg-Ca0.3 presented similar XRD spectra[45].…”

“…The Ca 2+ ion and its compounds (phosphate type) can be tolerated (low toxicity) by the human body at relatively high levels of ~4 g/day. The Mg-Ca alloys are also mechanically compatible with bone, biodegradable and exhibit interesting characteristics as a potential material for implants, providing cell adhesion (osteoconductivity) and cell growth stimulation on the implant surface [44,45]. In a previous study, we reported the antibacterial effect of Ag-NPs electroless deposited on the Mg-Ca0.3 surfaces, with a percentage inhibition of diameter growth (PIDG) of up to 64% against E. coli and 83% against S. aureus [45].…”

Microstructural Evolution and Electrochemical Behavior of Solution Treated, Hot Rolled and Aged MgDyZnZr Alloy

“…Figure 10 shows the equivalent electrical circuit used [31] to model the experimental impendance data, which includes, as the main components, the solution resistance (R s ), a constant phase element (CPE 1 ) and a resistor (R 1 ), associated with the double layer and charge transfer resistor (substrate/electrolyte interface) [42,43]. The (CPE 2 ) and the resistance (R 2 ) are characteristic of the corrosion process at the metal surface through the corrosion layer and the release of Mg ions.…”

The Effect of Co-Encapsulated GO-Cu Nanofillers on Mechanical Properties, Cell Response, and Antibacterial Activities of Mg-Zn Composite

“…These devices are thought to provide adequate mechanical properties at the fracture site during new bone tissue healing before being replaced by natural tissue. Mg-based biomaterials have been the topic of comprehensive study over the last two decades [11][12][13][14]. However, the appropriateness of Mg alloys as a fracture fixation system has been questioned because of their low resistance to corrosion and relatively inferior mechanical properties.…”