Carbon nanotubes are highly versatile materials; new applications using them are continuously being developed. Special attention is being dedicated to the possible use of multiwall carbon nanotubes in biomaterials contacting with bone. This study describes the response of murine macrophage-like Raw 264.7 cells after two and six days of culture in contact with artificially generated particles from both, ultra-high molecular weight polyethylene polymer and the composite (multiwall carbon nanotubes and ultra-high molecular weight polyethylene). This novel composite has superior wear behavior, having thus the potential to reduce the number of revision knee arthroplasty surgeries required by wear failure of tibial articulating component and diminish particle-induced osteolysis. The results of an in vitro study of viability, and interleukin-6 and tumor necrosis factor-alpha production suggest good cytocompatibility, similar to that of conventional ultra-high molecular weight polyethylene.

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Ultra-high molecular weight polyethylene (UHMWPE) has proven to be a good counterpart articulating surface against Cr-Co-Mo femoral components in artificial joints. Nevertheless, UHMWPE wear damage and subsequent aseptic loosening continues to be the main reason for revision of knee replacements. There is an ongoing research effort to improve the metal-on-UHMWPE couple. This study compares the wear resistance of multiwalled carbon nanotube-reinforced UHMWPE composite with conventional orthopedic grade UHMWPE currently used in total knee replacements. Defined by previous studies, 1.25 wt.% multiwall carbon nanotubes (MWCNT) were incorporated into UHMWPE to fabricate UHMWPE-MWCNT composites by solution blending, achieving an even distribution in the polymeric matrix. UHMWPE-MWCNT samples were manufactured by compression molding and sterilized with γ-rays. Scanning electron microscopy confirmed a uniform distribution of the MWCNTs. The volumetric wear was reduced by 86.9%, and the indentation depth in creep testing decreased 68%. The composite displayed superior wear behavior producing less wear debris than conventional materials. K E Y W O R D Scomposites, mechanical properties, multiwall carbon nanotubes, ultra-high molecular weight polyethylene, wear debris