Investigating Single Molecule Adhesion by Atomic Force Spectroscopy |
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Authors: | Frank W. S. Stetter Sandra Kienle Stefanie Krysiak Thorsten Hugel |
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Affiliation: | 1.Physik-Department E22a, Technische Universität München;2.IMETUM, Technische Universität München |
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Abstract: | Atomic force spectroscopy is an ideal tool to study molecules at surfaces and interfaces. An experimental protocol to couple a large variety of single molecules covalently onto an AFM tip is presented. At the same time the AFM tip is passivated to prevent unspecific interactions between the tip and the substrate, which is a prerequisite to study single molecules attached to the AFM tip. Analyses to determine the adhesion force, the adhesion length, and the free energy of these molecules on solid surfaces and bio-interfaces are shortly presented and external references for further reading are provided. Example molecules are the poly(amino acid) polytyrosine, the graft polymer PI-g-PS and the phospholipid POPE (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine). These molecules are desorbed from different surfaces like CH3-SAMs, hydrogen terminated diamond and supported lipid bilayers under various solvent conditions. Finally, the advantages of force spectroscopic single molecule experiments are discussed including means to decide if truly a single molecule has been studied in the experiment. |
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Keywords: | Physics Issue 96 AFM functionalization single molecule polymer lipid adhesion atomic force microscopy force spectroscopy |
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