Development of Ti-Ta-Nb-Mo-Zr high entropy alloy by μ-plasma arc additive manufacturing process for knee implant applications and its biocompatibility evaluation

Abstract

It describes development of equiatomic Ti-Ta-Nb-Mo-Zr HEA by μ-plasma arc additive manufacturing process for knee implant applications, its microstructure study and in-vitro biocompatibility evaluation using cell viability, released metallic ions, and corrosion behaviour. Cell viability was evaluated by treating HeLa, HEK-293, and BHK cells with 20, 40, 60, and 100 μl concentrations of prepared media for the developed HEA for 24, 48, 72 h incubation durations. Released amounts of Ti, Ta, Nb, Mo, and Zr ions were estimated in 4.4

5.4

and 7.4 pH value simulated body fluid solution (SBF) for immersion durations of 1, 3, and 7 weeks. Corrosion behaviour was studied in 4.4

5.4

and 7.4 pH value SBF solution at 37 °C. Ti-Ta-Nb-Mo-Zr HEA consists of BCC major and minor phases having fine dendritic and inter-dendritic structure. Average % cell viability decreased with increase in prepared media concentration. Overall average values of viability for HeLa, HEK-293, and BHK cells treated with prepared media are 90%

88%

and 92% respectively. BHK cells showed maximum cell viability at each media concentration and for each incubation duration. Ti-Ta-Nb-Mo-Zr HEA did not harm appearance of HeLa, HEK-293, and BHK cells. Overall averaged released amounts of Ti, Ta, Nb, Mo, and Zr ions are 37, 26

57

38, and 28 ppb respectively. Ti-Ta-Nb-Mo-Zr HEA has minimum values of all essential corrosion parameters without causing any pitting. It showed excellent biocompatibility hence referred as bio-HEA which is a new class of biomaterials for knee implants that can overcome limitations of the present materials. © 2022 The Author(s).