title: Strain in UHMWPE for orthopaedic use studied by Raman microprobe spectroscopy.
abstract: Ultra-high-molecular-weight polyethylene (UHMWPE) has been the most popular bearing material against both metal and ceramic counter-faces in total hip and knee joint replacements. Therefore, it is desirable to clarify the complex phenomena occurring both in vivo and in vitro, using highly sensitive analytical techniques. However, conventional analytical techniques used so far suffer from destructive measurements, lack of precision and/or intricate techniques. In the present study, the physical and chemical properties of both conventional UHMWPE (PE) and highly cross-linked UHMWPE (CLPE) were investigated by Raman microprobe spectroscopy, which combines the advantages of high precision and non-destructive measurements. It was found that the strain of UHMWPE can be evaluated by a change in the full width at half maximum (FWHM) of a selected Raman band (located at around 1127 cm(-1)), and that these spectroscopic strain coefficients were (0.42 +/- 0.01) x 10(-2) cm(-1)/% elongation and (0.48 +/- 0.01) x 10(-2) cm(-1)/% elongation for PE and CLPE (100 kGy), respectively. The difference in the crystalline nature between PE and CLPE was also confirmed by Raman microprobe spectroscopy. In addition, the Raman microprobe spectroscopy technique enabled us to obtain hyperspectral images of strain and crystallinity on a microscopic scale. Thus, Raman microprobe spectroscopy is a very effective method for analyzing UHMWPE for orthopaedic use.
authors.affiliation: Research and Development Corporate Division, Japan Medical Materials Corporation, Uemura Nissei Bldg. 9F 3-3-31 Miyahara, Yodogawa-Ku, Osaka 532-0003, Japan. kyomotom@jmmc.jp
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kyomoto
authors.forename: Yasutake
authors.initials: Y
authors.lastname: Miwa
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pezzotti
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D003432:Cross-Linking Reagents; D003460:Crystallization; D066298:In Vitro Techniques; D008422:Materials Testing; D008854:Microscopy, Electron; D011095:Polyethylenes / Q000737:chemistry*; D019736:Prostheses and Implants; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene