Berlin 2018 – scientific programme
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BP: Fachverband Biologische Physik
BP 11: Bioimaging and Biopspectroscopy I
BP 11.9: Talk
Tuesday, March 13, 2018, 12:00–12:15, H 1028
Imaging in Biologically-Relevant Environments with AFM Using Stiff qPlus Sensors — •Korbinian Pürckhauer1, Alfred J. Weymouth1, Katharina Pfeffer1, Lars Kullmann1, Estefania Mulvihill2, Michael P. Krahn3, Daniel J. Müller2, and Franz J. Giessibl1 — 1University of Regensburg, Regensburg, Germany — 2ETH Zürich, Basel, Switzerland — 3University Hospital of Münster, Münster, Germany
High-resolution imaging of soft biological samples with atomic force microscopy (AFM) is challenging because they need to be imaged with very low forces to prevent deformation. Typically, AFM of those samples is performed with soft silicon cantilevers (k≈ 0.1−10 N/m) and optical detection in a liquid environment.
In this work we demonstrate the advantages of using stiffer sensors (k≈1 kN/m) which were used to obtain unprecedented spacial resolution of molecules in vacuum at low temperatures [1]. In liquid environments, the high stiffness of the qPlus sensor allows us to use small amplitudes in a non-contact mode and obtain high quality factors [2]. The samples are immersed in aqueous solution in a liquid cell and we use qPlus sensors with long tips, only submerging the tip apex.
Atomic resolution of muscovite mica was achieved in various solutions. To prove that we can non-destructively image soft biological samples with stiff sensors, we show images of lipid membranes and finally molecular resolution images of a lipid bilayer.[3]
[1] Gross et al., Science 325, 1110 (2009). [2] Ichii et al., Jpn. J. Appl. Phys. 51, 08KB08 (2012). [3] Pürckhauer et al., submitted.