1. Department of ChemistryUniversity of Toronto Toronto ON M5S 3H6 Canada
2. Institute of Macromolecular Compounds of the Russian Academy of Sciences Saint Petersburg 199004 Russia
3. Institute of Biomaterials and Biomedical Engineering Toronto ON M5S 3G9 Canada
4. Department of Chemical Engineering and Applied ChemistryUniversity of Toronto Toronto ON M5S 3E5 Canada