Masaru Matsuo
Dalian University of Technology, China
Title: A multi-layered composite ensuring harmless to the human body and implant longevity of hip prosthesis in orthopedics
Biography
Biography: Masaru Matsuo
Abstract
Implant longevity of hip prosthesis in orthopedics is one of the current topics to support the activities of the elderly. The present work is focused on the drastic improvement for the wear resistance and reduction of the surface friction of the acetabular cup as a bearing material in femoral head. In actual orthopedics, cross-linked polyethylene (PE) has been used in orthopedics as a bearing material in artificial joints. However, wear damages of PE have been one of the factors limiting implant longevity. That is, the resultant wear of polyethylene bearing purportedly produces billions of wear particles with submicron-size that cause adverse pathological reaction in the surrounding tissues leading to osteolysis and joint loosening. To avoid the serous problem, ultra-high molecular weight PE (UHMWPE)/hydroxyapatite (HA) composite was prepared as a substrate layer by the solution-gel method. As for the second layer, porous UHMWPE/HA composite was prepared by using NaCl as the porogen and then poly(vinyl alcohol) (PVA) was filled into the pores of UHMWPE/HA composite. The porosity of the UHMWPE/HA composite was more than 50%, and the pore distribution was uniform. A majority of pores were perfoliate and crammed with PVA gel. PVA/Laponite-HA layer-by-layer (LBL) self-assembly film was prepared as a surface layer, in which Laponite acted as a template to improve the dispersion of HA in water. The UHMWPE/HA substrate layer and the porous UHMWPE/HA layer filled with PVA hydrogel were pressed under 180 oC, and then they were combined with the surface layer of LBL film to form a multi-layered composites. The prepared multi-layered composite has a very low friction coefficient (0.017) under a load of 1200 N, which is similar to the friction coefficient of natural articular cartilage.