1. Dainton Building, Department of Chemistry, The University of Sheffield, Brook Hill, Sheffield, S3 7HF, United Kingdom, Department of Engineering Materials, The University of Sheffield, The Kroto Research Institute, Broad Lane, Sheffield, S3 7HQ, United Kingdom, and Biocompatibles UK Ltd., Chapman House, Farnham Business Park, Weydon Lane, Farnham, Surrey, GU9 8QL, United Kingdom