Production and mechanical properties of Ti–5Al–2.5Fe– x Cu alloys for biomedical applications

Abstract

In this study, the mechanical, antibacterial properties and cell toxicity response of Ti-5Al2.5Fe alloy with different copper contents were investigated. The alloys were prepared by high-energy ball milling using elemental Ti, Al, Fe, and Cu powders and consolidated by a uniaxial vacuum hot press. Staphylococcus aureus strain ATCC 29213 and Escherichia coli strain ATCC 25922 were used to determine the antibacterial properties of the sintered alloys. The in vitro cytotoxicity of the samples was evaluated with HeLa (ATTC, CCL-2) cells using thiazolyl blue tetrazolium bromide. The mechanical behavior of the samples was determined as a function of hardness and bending tests and analyzed by scanning electron microscopy, energy dispersive x-ray spectroscopy, optical microscopy and x-ray diffraction (XRD). The results showed that the Cu content significantly improved the antibacterial properties. Cu addition prevented the formation of E. coli and S. aureus colonies on the surface of the samples. All samples exhibited very good cell biocompatibility. The alloys with different copper contents showed different mechanical properties, and the results were correlated by microstructural and XRD analyses in detail. Our results showed that Cu has a great effect on the Ti5Al2.5Fe alloy and the alloy is suitable for biomedical applications with enhanced antibacterial activity.

Recent Advances in Research on Antibacterial Metals and Alloys as Implant Materials

“…The MIC and minimum bactericidal concentration of Zn 2+ for S. aureus are 10 −7 mol/L and 2.5 × 10 −7 mol/L, respectively (Ning et al, 2015). The IC 50 values of Zn 2+ for L929 and MC3T3-E1 are 9.28 × 10 −5 and 9 × 10 −5 mol/ L, respectively, which are higher than those of Ag and Cu ions (Yamamoto et al, 1998). The main antibacterial mechanism of Zn 2+ is the destruction of the outer membrane of the bacteria, its binding to enzymatic active sites, and competitive inhibition of the biological activity of the cell (Ye et al, 2020).…”

“…The minimum inhibitory concentration (MIC) of Ag ions for both S. aureus and E. coli is 10 −7 mol/L (Ning et al, 2015). As for the cytotoxicity, the median inhibitory concentration (IC 50 ) values of Ag ions for L929 fibroblasts and MC3T3-E1 osteoblastic cells are 4.25 × 10 −6 and 2.77 × 10 −6 mol/L, respectively (Yamamoto et al, 1998). In vitro studies have shown that 2.5 × 10 −7 mol/L to 10 −6 mol/L of Ag + exhibits antibacterial effects against S. aureus and E. coli (antibacterial rate > 90%) and no cytotoxicity against eukaryotic cells (Ning et al, 2015).…”

“…Cu has a killing effect on various bacteria, including those that are gram-positive (S. aureus and S. epidermidis), gram-negative (E. coli and P. aeruginosa), and multi-drug resistant (MRSA and MRSE), and viruses. The MIC of Cu 2+ for S. aureus is in the range of 1-111 × 10 −6 mol/L, whereas the IC 50 values of Cu 2+ for L929 fibroblasts and MC3T3-E1 osteoblastic cells are 4.15 × 10 −5 and 1.59 × 10 −5 mol/L, respectively (Yamamoto et al, 1998;Ning et al, 2015). Owing to its potent and rapid antibacterial properties, Cu is the first metal antibacterial agent approved by the US Environmental Protection Agency.…”

Effect of silver content on the wear and mechanical properties of powder metallurgical Ti-5Al-2.5Fe-xAg alloys

“…Therefore, many researchers suggested that alloying of Ti with copper and silver can increase tribological properties, while antibacterial properties still remain [10][11][12][13]. In our previous study [14] different content of Cu addition in Ti-5Al-2.5Fe was investigated and the results showed that Cu addition affects mechanical properties in a small range whilst still showing good J. Min. Metall.…”

Ternary Ti alloys functionalised with antibacterial activity

“…However, the authors also reported that too high Mn concentrations should be avoided because of known risk of Mn intoxication as well as embrittlement of the alloy. Modification of conventional compositions has also been attempted by Yamanoglu et al 11 who added 1-5 wt.% of Cu to the Ti-5Al-2.5Fe alloy hot pressed at 950 °C during 30 min under an applied pressure of 50 MPa. It was found that the antibacterial activity was enhanced by the addition of Cu and the cytotoxicity level remained within the standard values although the cell count was reduced as the amount of Cu increased.…”