1. Laboratory of Biophysics and Surface Analysis, School of Pharmacy, The University of Nottingham, NG7 2RD, U.K., Advanced Drug Delivery Group, School of Pharmacy, The University of Nottingham, Nottingham, NG7 2RD, U.K., Department of Chemistry, Sheffield University, Sheffield, S3 7HF, U.K., and Biocompatibles Ltd., Farnham Business Park, Farnham, Surrey, GU9 8QL, U.K.