Evaluation of pristine and Eu2O3-added MgB2 ceramics for medical applications: hardness, corrosion resistance, cytotoxicity and antibacterial activity

• MgB2 added with nano- or micro-Eu2O3 was obtained by ex-situ spark plasma sintering.
• PBS containing MgB2-based samples shows a pH of 8.5, lower than that for Mg (11).
• MgB2-based samples have lower electro-corrosion rates than Mg.
• Vickers hardness is 6.8–10.2 GPa, higher than that for biodegradable Mg-based alloys.
• MgB2 has good antibacterial activity against E. coli and mild one against S. aureus.

Nano- or micropowders of Eu2O3 were added to MgB2, resulting in a composition of (MgB2)0.975(EuO1.5)0.025. Pristine and doped samples were prepared using spark plasma sintering and tested for (i) Vickers hardness, (ii) pH evolution in phosphate-buffered saline solution, (iii) corrosion resistance (Tafel polarization curves), (iv) cytotoxicity (in vitro tests), and (v) antibacterial activity. Eu2O3 addition influenced the investigated properties. Solutions of MgB2-based samples show a relatively high saturation pH of 8.5. This value is lower than that of solutions incubated with Mg or other Mg-based biodegradable alloys reported in the literature. MgB2-based samples have lower electro-corrosion rates than Mg. Their Vickers hardness is 6.8–10.2 GPa, and these values are higher than those of biodegradable Mg-based alloys. MgB2 has low in vitro biocompatibility, good antibacterial activity against Escherichia coli, and mild activity against Staphylococcus aureus. Our results suggest that MgB2-based materials deserve attention in biomedical applications, such as implants or sterile medical instruments.