title: Nanomechanical and tribological characterization of the MPC phospholipid polymer photografted onto rough polyethylene implants.
abstract: Grafting biomimetic polymers onto biomaterials such as implants is one of the promising approaches to increase their tribological performance and biocompatibility and to reduce wear. In this paper, poly(2-methacryloyloxyethyl phosphorylcholine) (p(MPC)) brushes were obtained by photografting MPC from the rough surface of ultra high molecular weight polyethylene (UHMWPE) joint implants. Such substrates have a high roughness (Ra∼650nm) which often has the same order of magnitude as the brush thickness, so it is very difficult to estimate the vertical density profile of the grafted content. The quality of the p(MPC) grafting was evaluated through a wide range of characterization techniques to reveal the effectiveness of the grafting: atomic force microcopy (AFM) imaging and force spectroscopy, contact angle, SEM/EDX, and confocal microscopy. After testing the methods on smooth glass substrate as reference, AFM nano-indentation proves to be a reliable non destructive method to characterize the thickness and the mechanical properties of the p(MPC) layer in liquid physiological medium. Tribological measurements using a homemade biotribometer confirm that, despite heterogeneity thickness (h=0.5-6μm), the p(MPC) layer covers the roughness of the UHMWPE substrate and acts as an efficient lubricant with low friction coefficient and no wear for 9h of friction.
authors.affiliation: Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France.
authors.forename: Na
authors.initials: N
authors.lastname: Wang
authors.forename: Ana-Maria
authors.initials: AM
authors.lastname: Trunfio-Sfarghiu
authors.forename: Daniel
authors.initials: D
authors.lastname: Portinha
authors.forename: Sylvie
authors.initials: S
authors.lastname: Descartes
authors.forename: Etienne
authors.initials: E
authors.lastname: Fleury
authors.forename: Yves
authors.initials: Y
authors.lastname: Berthier
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Rieu
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D017276:Friction; D054327:Lubricants / Q000737:chemistry*; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000737:chemistry; D055668:Photochemical Processes; D011095:Polyethylenes / Q000737:chemistry*; D011109:Polymethacrylic Acids; D019736:Prostheses and Implants; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D054327:Lubricants; D008689:Methacrylates; D011095:Polyethylenes; D011109:Polymethacrylic Acids; C115766:poly(2-methacryloyloxyethyl-phosphorylcholine); D010767:Phosphorylcholine