Development of Co-Cr-Mo-xTi alloys by micro-plasma-based 3D printing for knee implant applications and its biocompatibility assessment

Abstract

It reports development of Co-Cr-Mo-xTi alloys as biomaterial by μ-plasma-based 3D-printing for knee implant applications and its in-vitro biocompatibility assessment using cell viability, metallic ion release, and corrosion behavior analysis. HeLa cells treated with 16.6, 33.3, 66.6, and 106.6 µl concentration of the prepared media were used to study cell viability for 24, 48, and 72h incubation duration. Metallic ion release was assessed in phosphate buffer saline (PBS) solution of 4.0, 5.5, and 7.5 pH values using 1, 3, and 7week immersion durations. Corrosion rate was assessed in 7.4 pH PBS solution at 37 °C. Overall average cell viability of Co-Cr-Mo-2Ti, Co-Cr-Mo-4Ti, and Co-Cr-Mo-6Ti alloys was found to be 92%, 95%, and 85%, respectively. Co-Cr-Mo-xTi alloys did not have any harmful effects on the appearance of HeLa cells. The overall averaged released amounts of Co, Cr, Mo, and Ti ions by Co-Cr-Mo-xTi alloys are 126, 41, 11, and 9 parts per billion, respectively. Corrosion behavior of Co-Cr-Mo-xTi alloys showed passive plateau up to 0.5 V potential without causing any pitting. Co-Cr-Mo-4Ti alloy has minimum values of all important parameters of corrosion and shows formation of TiO2 passive oxide layer imparting better corrosion resistance than Co-Cr-Mo alloy. The addition of Ti to Co-Cr-Mo alloy is advantageous due to the formation of non-cytotoxic, cell growth activating, and metallic ion release minimizing intermetallic CoTi2 phase. This study identifies Co-Cr-Mo-4Ti alloy as better biocompatible biomaterial that could be safely used as knee implant material owing to its better cell viability, metallic ion release, and corrosion behavior. Graphical Abstract: [Figure not available: see fulltext.]. © 2023, The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.