1. Nanotechnology and Bio-Engineering Research Group, Department of Environmental Science, Faculty of Science, Institute of Technology Sligo, Ash Lane, Sligo F91 YW50, Ireland
2. Centre for Precision Engineering, Materials and Manufacturing Research (PEM), Institute of Technology Sligo, Ash Lane, Sligo F91 YW50, Ireland
3. Tyndall National Institute, University College Cork, Lee Maltings, Dyke Parade, Cork T12 R5CP, Ireland
4. The Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences, University of Surrey,
Guildford, Surrey GU2 7XH, United Kingdom