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Updated: May 2, 2026
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Multi-Scale Modification of Metallic Implants With Pore Gradients, Polyelectrolytes and Their Indirect Monitoring In vivo
Published on: July 1, 2013
10.9K
Gd Added Mg Alloy for Biodegradable Implant Applications
Arun Kumar Surendran1,2, Jithu Jayaraj1,2, Rajinikanth Veerappan2,3
1Material Science and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram, India.
Summary
This study investigated magnesium alloys with varying zinc/gadolinium ratios, finding Mg-10Gd-1Zn-0.5Zr exhibited superior mechanical strength and biocompatibility due to its unique phase composition and protective degradation film.
Area of Science:
- Materials Science
- Biomaterials Engineering
- Metallurgy
Background:
- Magnesium (Mg) alloys are promising biodegradable materials for biomedical applications.
- Controlling alloy composition, specifically the zinc (Zn) to gadolinium (Gd) ratio, is crucial for tailoring microstructure and properties.
- Understanding the influence of secondary phases on mechanical and biological behavior is essential for alloy development.
Purpose of the Study:
- To investigate the effect of varying Zn/Gd ratios on the microstructure, mechanical properties, and in vitro/in vivo behavior of extruded Mg alloys.
- To identify the optimal alloy composition for enhanced strength, controlled degradation, and biocompatibility.
Main Methods:
- Extrusion of Mg alloys with different Zn/Gd ratios: Mg-2Gd-2Zn-0.5Zr (Zn/Gd=1), Mg-2Gd-6Zn-0.5Zr (Zn/Gd=3), and Mg-10Gd-1Zn-0.5Zr (Zn/Gd=0.1).
- Characterization of microstructure and secondary phases (W, (Mg,Zn)3Gd, LPSO, I).
- Evaluation of mechanical properties (yield strength, tensile strength, elongation).
- In vitro assessment of cell viability and proliferation.
- In vivo subcutaneous implantation in rats for 1 month to evaluate degradation rate and toxicity.
Main Results:
- The Zn/Gd ratio significantly influenced the types and distribution of secondary phases (W, (Mg,Zn)3Gd, LPSO, I).
- Mg-10Gd-1Zn-0.5Zr alloy demonstrated superior mechanical properties, with yield strength of 270 MPa and tensile strength of 330 MPa, and 12% elongation.
- The presence of Gadolinium oxide (Gd2O3) in the degradation film of Mg-10Gd-1Zn-0.5Zr enhanced corrosion resistance, leading to lower biodegradation rates.
- Mg-10Gd-1Zn-0.5Zr showed improved cell viability and proliferation in vitro and exhibited a low degradation rate (0.35 mm/y) without inducing toxicity in vivo.
Conclusions:
- The Zn/Gd ratio is a critical factor in determining the microstructure and properties of Mg alloys.
- Mg-10Gd-1Zn-0.5Zr alloy offers an excellent combination of mechanical strength, controlled biodegradability, and biocompatibility.
- This alloy holds significant potential for applications in biomedical implants, particularly where enhanced performance and safety are required.
