Evaluation of Ni-free Zr–Cu–Fe–Al bulk metallic glass for biomedical implant applications

Abstract

This study was conducted to investigate the surface characteristics, including the chemical composition, metal ion release, protein adsorption, and cell adhesion, of a Ni-free Zr-based (Zr62.5Cu22.5Fe5Al10) bulk metallic glass (BMG) with low elastic modulus for biomedical implant applications. X-ray photoelectron spectroscopy was used to identify the surface chemical composition and the protein (albumin and fibronectin) adsorption of the specimen. The metal ions released from the specimen in simulated blood plasma and artificial saliva solutions were measured using an inductively coupled plasma-mass spectrometer. The cell adhesion, in terms of the morphology, focal adhesion complex, and skeletal arrangement, of human bone marrow mesenchymal stem cells was evaluated using scanning electron microscope observations and immunofluorescent staining. For comparison purposes, the above-mentioned tests were also carried out on the widely used biomedical metal, Ti. The results showed that the main component on the outermost surface of the amorphous Zr62.5Cu22.5Fe5Al10 BMG was ZrO2 with small amounts of Cu, Al, and Fe oxides. The released metal ions from Zr62.5Cu22.5Fe5Al10 BMG were well below the critical concentrations that cause negative biological effects. The Zr62.5Cu22.5Fe5Al10 BMG had a greater adsorption capacity for albumin and fibronectin than that of commercial biomedical Ti. The Zr62.5Cu22.5Fe5Al10 BMG surface showed an attached cell number similar to the Ti surface but had better cell adhesion morphology and cytoskeletal arrangement. Based on the present results, the Ni-free Zr62.5Cu22.5Fe5Al10 BMG has the potential to be used for biomedical implant applications.