1. Laboratoire de Biomatériaux et Polymères de Spécialité (LBPS/B2OA - UMR 7052), Institut Galilée, Université Paris 13, 93430 Villetaneuse, France, and National ESCA and Surface Analysis Center for Biomedical Problems, Departments of Bioengineering and Chemical Engineering, Box 351750, University of Washington, Seattle, Washington 98195-1750