1. UMR 2142-CNRS/bioMérieux Systèmes Macromoléculaires et Immunovirologie Humaine, E.N.S.L., 46, allée d'Italie, 69364 Lyon Cedex 07, France
2. Nanostructured Polymers Research Center, Parsons Hall, 23 College Road, University of New Hampshire, Durham, New Hampshire 03824