In Vitro Corrosion and Biological Assessment of Bioabsorbable WE43 Mg Alloy Specimens

Emmet Galvin,Caitríona Lally,Brendan Duffy,Bryan Macdonald,Swarna Jaiswal

doi:10.3390/jmmp1010008

Abstract

Bioabsorbable magnesium (Mg) alloys have several advantages in biomedical implant applications as they reduce certain risks associated with conventional permanent implants. However, limited information is available for WE43 Mg alloy specimens with comparable size to that of biomedical implants such as cardiovascular stents and orthopaedic wires. The present work examines the corrosion and biological properties of WE43 stent precursor tubes and wire specimens suited for orthopaedic implants. The corrosion-induced loss of mechanical integrity as well as the corrosion-induced changes in surface morphology of the specimens are elucidated and compared. Cell viability assays were performed with human umbilical vein endothelial cells (HUVECs). It was observed that Mg ions released from the WE43 alloy acted as a growth stimulator of HUVECs.

Highlights

Mg and its alloys have emerged as a new class of biomaterials for use in bioabsorbable medical devices such as stents [1,2] and orthopaedic implants [3]
A total of 27 dog-bone and 18 wire specimens having the geometry and dimensions shown in Figure 1 were laser cut from stent precursor tubes and cleaved from wires of the WE43 Mg alloy, respectively, which contained approximately 93% Mg, 4% yttrium (Y), 2.3% neodymium (Nd), 0.7% zirconium (Zr), and the remainder of rare-earth (RE) elements, as measured by inductively coupled plasma mass spectrometry (7500 ICP-MS, Agilent Technologies, Santa Clara, CA, USA)
A relatively uniform corrosion attack was observed in this study when compared to previous studies involving bulk specimens and specimens prepared by surface treatments unsuited to medical device manufacture such as mechanical polishing using silicon carbide papers [14]

Summary

Introduction

Mg and its alloys have emerged as a new class of biomaterials for use in bioabsorbable medical devices such as stents [1,2] and orthopaedic implants [3]. Few studies have been published that examine the in vitro corrosion performance of WE43 stent precursor tubes and stents [10,11,12,13] and WE43 wires suited for use as orthopaedic implants [14,15,16]. While some data relating to the performance of WE43 dog-bone specimens was presented in our previous study [12], the main aim of this study is to compare and contrast the in vitro corrosion and biological performance of WE43 specimens prepared from stent precursor tubes and wires

Objectives

Methods

Results

Conclusion