1. Department of Chemical and Biomolecular Engineering, Hong Kong Univ. of Science and Technology, Clearwater Bay, HK.
2. Department of Chemical Engineering and Biotechnology, New Museums Site, Pembroke Street, Univ. of Cambridge, Cambridge CB2 3RA, GB.
3. Department of Chemical and Biomolecular Engineering, Hong Kong Univ. of Science and Technology, Clearwater Bay, HK (Corresponding author), e-mail: kemckayg@ust.hk