In vitro degradation and biocompatibility of Mg-Nd-Zn-Zr alloy

Yongping Wang,Jialin Niu,Yao Jiang,Guangyin Yuan,Jian Zhang,Yaohua He,Lin Mao,Zhaojin Zhu

doi:10.1007/s11434-012-5066-6

Yongping Wang, Jialin Niu + Show 6 more

Open Access

https://doi.org/10.1007/s11434-012-5066-6

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Abstract

In this study, in vitro degradation and biocompatibility of Mg-Nd-Zn-Zr (NZK) alloy were investigated to determine its suitability as a degradable medical biomaterial. Its corrosion properties were evaluated by static immersion test, electrochemical corrosion test, scanning electron microscopy (SEM), and energy dispersive spectroscopic (EDS) analysis, and in vitro biocompatibilities were assessed by hemolysis and cytotoxicity tests. Pure magnesium was used as control. The results of static immersion test and electrochemical corrosion test in simulated body fluid (SBF) demonstrated that the addition of alloying elements could improve the corrosion resistance. The hemolysis test found that the hemolysis rate of calcium phosphate coated NZK alloy was 4.8%, which was lower than the safe value of 5%. The cytotoxicity test indicated that NZK alloy extracts did not significantly reduce MC3T3-E1 cell viability. Hemolysis test and cytotoxicity test display excellent hemocompatibility and cytocompatibility of NZK alloy in vitro. Our data indicate that NZK alloy has excellent biocompatibility and thus can be considered as a potential degradable medical biomaterial for orthopedic applications.

Highlights

In this study, in vitro degradation and biocompatibility of Mg-Nd-Zn-Zr (NZK) alloy were investigated to determine its suitability as a degradable medical biomaterial
To determine the elemental compositions of the particles formed on the surface of NZK alloy during the static immersion test, energy dispersive spectroscopic (EDS) analysis was performed, which revealed that these particles were mainly composed of oxygen, carbon, sodium, Figure 1 Microstructure and degradation behaviour of NZK alloy. (a) Optical micrograph of NZK alloy; (b) scanning electron microscopy (SEM) micrographs of NZK alloy; (c) the surface of the NZK alloy was rough with a layer of off-white degradation products after 30 d immersion in simulated body fluid (SBF); (d) corrosion morphologies of NZK alloy after removing degradation products using chromic acid
After the corrosion products were removed by 200 g/L chromic acid, corrosion pits can be clearly seen on the surface of NZK alloy (Figure 1(d))

Summary

Introduction

In vitro degradation and biocompatibility of Mg-Nd-Zn-Zr (NZK) alloy were investigated to determine its suitability as a degradable medical biomaterial. Our data indicate that NZK alloy has excellent biocompatibility and can be considered as a potential degradable medical biomaterial for orthopedic applications. Magnesium alloys are corroded in physiological environments, and have become a promising degradable medical biomaterial, attracting much attention in recent years [5,6,7,8] because of their degradability, and their good biocompatibility, low density, and suitable mechanical properties such as high specific strength and elastic modulus approximating that of human bone [9,10,11]. It is expected that this work may help to confirm the medical safety of NZK alloy and obtain a new promising degradable magnesium alloy

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