1. Department of Materials Department of Bioengineering and Institute of Biomedical Engineering Imperial College London London SW7 2AZ United Kingdom
2. Department of Medical Biochemistry and Biophysics Karolinska Institute Stockholm 17177 Sweden
3. Department of Chemistry and York Biomedical Research Institute University of York Heslington YO10 5DD United Kingdom
4. School of Engineering RMIT University Melbourne Victoria 3001 Australia
5. Present Addresses: Department of Engineering and Design, School of Engineering and Informatics, University of Sussex BN1 9RH Brighton United Kingdom
6. Present Addresses: Department of Mathematics and Physics North South University, Bashundhara Dhaka 1229 Bangladesh