High-precision electrical AFM modes for biological applications

Electrical modes of Atomic Force Microscopy (AFM) allow the high-resolution mapping of surface charges on a sample with nanometer precision. A particular measurement challenge is to perform such modes on biological samples (tissue extracts, biomolecules, biomembranes, etc). To this end, the project aims to investigate different preparation and measurement approaches and a specific goal is to determine alterations of surface charge of biological fibers caused by the reaction with sugar, which has important implications in medicine and cell biology.

Figure 1: KFM surface potential map of a collagen fibril on graphite. The bright spots show areas of positive charge.

Project focus

• Determine the influence of humidity on ionised, chemical surface groups
• Investigate the charge of glycated protein fibrils

Project partners/collaborators

• Institute of Lightweight Design and Structural Biomechanics, TU Wien (Prof. P. Thurner)
• Department of Chemistry, University of Cambridge, UK (Prof. M. Duer)

Publications

• Kohl, D., P. Mesquida and G. Schitter (2017). “Quantitative AC – Kelvin Probe Force Microscopy.” Microelectronic Engineering 176: 28-32.
• P.Mesquida, D.Kohl, O.G.Andriotis, P.J.Thurner, M.J.Duer, S.B.Bansode, G.Schitter, Kelvin-probe Force Microscopy to map glycation of proteins, AFM Biomed Conference, Krakow 2017.