ACS Nano http://doi.org/bbwk (2016)

Total joint replacements frequently fail because wear debris from the prosthesis, which is typically made of ultrahigh molecular weight polyethylene (UHMWPE), can trigger an immune response. To prevent this, methods to modify the prosthesis exist including crosslinking of the polyethylene to improve tribological properties, using wear-resistant coatings, or adding filler materials to improve wear resistance. However, these methods can increase oxidation, peeling, and are potentially inflammatory, respectively. Xingyu Jiang and colleagues at the National Center for Nanoscience and Technology, and Southwest Jiaotong Univeristy now show that a composite of nanocrystalline cellulose and UHMWPE can reduce the generation of wear debris.

The composite was prepared by hot-pressing together blends of nanocrystalline cellulose and UHMWPE. Using water as the lubricant, wear resistance tests showed that composites with higher concentrations of cellulose had a lower coefficient of friction, fewer cracks, and less wear. Nanocrystalline cellulose aggregates similar in size to holes on the worn surfaces were seen, suggesting that the aggregates detached from the UHMWPE and helped prevent abrasion. Furthermore, the composite produced fewer and smaller debris than pure UHMWPE samples. When tested in cell cultures, the wear debris from the composite showed significantly lower inflammatory responses and cytotoxicity than pure UHMWPE. Although the results suggest that the composite may be a promising load-bearing material, it would be essential to test these materials under clinically relevant conditions.