1. Department of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, UK
2. Photon Science Institute, The Henry Royce Institute, University of Manchester, Manchester, M13 9PL, UK
3. BioAFM Facility, Faculty of Biology, Medicine and Health, Stopford Building, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
4. School of Chemical Engineering and Analytical Science, University of Manchester, M13 9PL, UK
5. Photon Science Institute, Department of Electrical and Electronic Engineering, University of Manchester, Manchester, M13 9PL, UK