Design and characterization of novel Ti-8Mo-xFe-yCu alloys as implant materials: Evaluation of biocompatibility, mechanical properties, and antibacterial potential

Abstract

Titanium and its alloys are highly desirable materials for biomedical metallic implants due to their superior specific strength, excellent corrosion resistance, and exceptional biocompatibility. Among these alloys, Ti6Al4V is widely used in practical biomedical applications because it offers an excellent combination of strength, fracture toughness, and corrosion resistance. However, recent research has revealed limitations in its biocompatibility attributed to the presence of toxic elements such as Al and V. In addition, it has been reported that Ti6Al4V is costly due to the addition of Vanadium and has the potential for post-implant inflammation. As a result, researchers have been investigating new biomedical beta-Ti alloys using biocompatible, affordable, and easily accessible beta-stabilizers like Mo, Fe, and Cu, to achieve similar performance as Ti6Al4V alloys. The present study aims to develop a novel biomedical alloy through the arc melting method, to obtain an implant material possessing low elastic moduli, biocompatibility, and antibacterial properties to mitigate the risk of post-implant inflammation. Microstructural analysis was conducted using microscopy and x-ray diffraction, while the mechanical properties were evaluated through micro vickers hardness testing machine and elastic moduli measurement utilizing the impulse excitation technique. Cytotoxicity assessment was performed using the (Cell Counting Kit-8) CCK-8 method, followed by an examination of the alloy's antibacterial properties using the point counting method. β-Ti single phase was obtained in this study with the addition of ≥1% Fe and ≥1% Cu. The Ti-8Mo-2Fe-2Cu alloy was found to have the lowest elastic moduli of 95 GPa. Electrochemical measurements show that the Ti-8Mo- xFe- yCu alloys have a lower corrosion current density of around 0.319–2.317 µA/cm2 compared to Ti6Al4V of 16.543 µA/cm2. The Ti-8Mo-1Fe-3Cu, Ti-8Mo-3Fe-1Cu, and Ti-8Mo-3Fe-3Cu alloys have comparable biocompatibility with Ti6Al4V with the viability of mesenchymal stem cells (MSCs) above 75% and have a positive antibacterial response. Ti-8Mo-3Fe-3Cu alloy demonstrates the most favorable blend of microstructure, mechanical attributes, corrosion resistance, cell viability, and antibacterial properties as an alternate biomaterial for implant applications.