Regensburg 2025 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 100: Focus Session Chemical Imaging for the Elucidation of Molecular Structure II (joint session O/BP)
O 100.6: Vortrag
Freitag, 21. März 2025, 12:15–12:30, H24
Imaging of the conformations of individual β-cyclodextrins with non-contact AFM — Marko Grabarics1, •Benjamin Mallada1,2,3, Shayan Edalatmanesh2,3, Stephan Rauschenbach1, Pavel Jelinek2,3, and Bruno de la Torre2 — 1Kavli Institute for Nanoscience Discovery, University of Oxford, UK — 2CATRIN, Palacký University Olomouc, CZ — 3Institute of Physics, Czech Academy of Sciences, CZ
Glycans, biopolymers essential to biology and materials science, are highly complex due to their structural diversity, conformational flexibility, and numerous possible isomers. Conventional methods often struggle to resolve these structures with atomic precision, especially under solvent-free conditions. We employ nc-AFM under UHV to determine the atomic structure of β-cyclodextrin (β-CD), a cyclic glucose molecule.
Our results reveal the adsorption geometries, hydroxy group positions, and stabilizing hydrogen bonds on a Au(111) surface. The primary face forms a closed hydrogen-bond network, while the secondary face exhibits pairwise interactions between OH groups of the same glucose monomer. DFT calculations validate these findings, enabling precise structural assignment and capturing subtle conformational differences.
This work highlights nc-AFM's capability to overcome the limitations of conventional sequencing techniques and represents the first application of nc-AFM to glycans. Future integration with ion deposition techniques could extend its utility to more complex glycans.
Keywords: nc-AFM; electrospray; glycan; single molecule; STM