In vitro and in vivo assessment of biomedical Mg–Ca alloys for bone implant applications

Abstract

Background: Magnesium (Mg)-based alloys are considered to be promising materials for implant application due to their excellent biocompatibility, biodegradability, and mechanical properties close to bone. However, low corrosion resistance and fast degradation are limiting their application. Mg-Ca alloys have huge potential owing to a similar density to bone, good corrosion resistance, and as Mg is essential for Ca incorporation into bone. The objective of the present work is to determine the in vitro degradation and in vivo performance of binary Mg-xCa alloy (x = 0.5 or 5.0 wt%) to assess its usability for degradable implant applications. Methods: Microstructural evolutions for Mg-xCa alloys were characterized by optical, SEM, EDX, and XRD. In vitro degradation tests were conducted via immersion test in phosphate buffer saline solution. In vivo performance in terms of interface, biocompatibility, and biodegradability of Mg-xCa alloys was examined by implanting samples into rabbit femoral condyle for 2 and 4 weeks. Results: Microstructural results showed the enhancement in intermetallic Mg 2 Ca phase with increase in Ca content. Immersion tests revealed that the dissolution rate varies linearly, with Ca content exhibiting more hydrogen gas evolution, increased pH, and higher degradation for Mg-5.0Ca alloy. In vivo studies showed good biocompatibility with enhanced bone formation for Mg-0.5Ca after 4 weeks of implantation compared with Mg-5.0Ca alloy. Higher initial corrosion rate with prolonged inflammation and rapid degradation was noticed in Mg-5.0Ca compared with Mg-0.5Ca alloy. Conclusions: The results suggest that Mg-0.5Ca alloy could be used as a temporary biodegradable implant material for clinical applications owing to its controlled in vivo degradation, reduced inflammation, and high bone-formation capability.

In vitro and in vivo biological performance of Mg-based bone implants

“…These results were supported by data obtained during in vivo studies (Li et al, 2008). Makkar et al (2018) evaluated the in vitro performance of binary Mg-xCa alloys (0.5 wt% and 5.0 wt %) for use as biodegradable biomaterials within bone. The results showed a better behaviour for the Mg-0.5Ca alloy in comparison to the Mg-5.0Ca alloy, both in terms of biocompatibility and corrosion resistance, suggesting that the Mg-0.5Ca alloy could be used as a biodegradable base material for clinical applications.…”

The current trends of Mg alloys in biomedical applications—A review

“…The in vivo studies of Mg–Ca‐based alloys can be found in the literature . Erdmann et al evaluated the mechanical and degradation performance of Mg–0.8Ca screws by implanting them in the tibia bones of rabbits.…”

Mg–Phenolic Network Strategy for Enhancing Corrosion Resistance and Osteocompatibility of Degradable Magnesium Alloys

“…The time checkpoints were set as day 1, day 3, week 1, week 2, and week 3. The PBS solutions were refreshed every 2 days with 500 μL of a fresh solution using a method similar to that mentioned in refs (51) and (52). At the end of each interval, the concentration of Mg 2+ ions released into the extracted PBS solution was determined using inductively coupled plasma optical emission spectroscopy (ICP-OES 700, Agilent) after measuring the pH value of the extracted using a pH meter (Thermo Fisher Scientific) in each time checkpoints.…”