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  • Feb 18 / 2016
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implants, biomedical

Implant materials: Reducing wear debris

ACS Nano, 2016, 10 (1), pp 298–306 – Ai Lin Chun – Nature Nanotechnology – Published 03 February 2016

Total joint replacements frequently fail because wear debris from the prosthesis, which is typically made of ultrahigh molecular weight polyethylene, can trigger an immune response. To prevent this, scientists formed a composite of polyethylene and cellulose nanocrystals as a strengthener to increase the wear resistance to minimize the wear debris.

Nanocrystalline Cellulose Improves the Biocompatibility and Reduces the Wear Debris of Ultrahigh Molecular Weight Polyethylene via Weak Binding

Shiwen Wang†‡, Qiang Feng†, Jiashu Sun*†, Feng Gao†, Wei Fan†, Zhong Zhang†, Xiaohong Li*‡, and Xingyu Jiang*†
† Beijing Engineering Research Center for BioNanotechnology & CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, National Center for NanoScience and Technology, 11 Beiyitiao, ZhongGuanCun, Beijing 100190, China
‡ Key Laboratory of Advanced Technologies of Materials, Ministry of Education of China, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China

nn-2015-04393k_0011Abstract – The doping of biocompatible nanomaterials into ultrahigh molecular weight polyethylene (UHMWPE) to improve the biocompatibility and reduce the wear debris is of great significance to prolonging implantation time of UHMWPE as the bearing material for artificial joints. This study shows that UHMWPE can form a composite with nanocrystalline cellulose (NCC, a hydrophilic nanosized material with a high aspect ratio) by ball-milling and hot-pressing. Compared to pure UHMWPE, the NCC/UHMWPE composite exhibits improved tribological characteristics with reduced generation of wear debris. The underlying mechanism is related to the weak binding between hydrophilic NCC and hydrophobic UHMWPE. The hydrophilic, rigid NCC particles tend to detach from the UHMWPE surface during friction, which could move with the rubbing surface, serve as a thin lubricant layer, and protect the UHMWPE substrate from abrasion. The biological safety of the NCC/UHMWPE composite, as tested by MC3T3-E1 preosteoblast cells and macrophage RAW264.7 cells, is high, with significantly lower inflammatory responses/cytotoxicity than pure UHMWPE. The NCC/UHMWPE composite therefore could be a promising alternative to the current UHMWPE for bearing applications.