Atomic force microscope for high-speed, nanomechanical and electrochemical characterizations

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Our various research activities in the fields of physics, nanoscience and cell biology require nanoscale resolution atomic force microscopy (AFM) capable of high-speed and advanced nanomechanical characterization of adhesive biological samples under physiologically relevant conditions as well as nanoscale electrochemistry. The 2. Physics Institute (leading applicant) with research focus on DNA-nanotechnology and nanophotonics, will predominantly employ the AFM to morphologically characterize DNA-origami-based nano-/microarchitectures as well as their dynamical functionalities. The 2. Physics Institute will further apply AFM-based scanning electrochemical microscopy (SECM), where electrochemical reactions can be triggered and monitored beneath the AFM tip with nanometer resolution, to realize reconfigurable nanophotonic (polymer) metasurfaces offering different functionalities, e.g. holography. It will also be used by the 4. Physics Institute to characterize the swelling and shrinking behaviour of conducting polymers. The Institute of Biomaterials and Biomolecular Systems (IBBS) will utilize the AFM to investigate the function and regulation of transport processes across biological membranes. IBBS further seeks to assess the static and dynamically changing material properties in tailored 2D and 3D hydrogels to control biological cellular responses. The Institute of Cell Biology and Immunology will use the AFM to measure cell and tissue mechanics and investigate how epithelial cell behaviour is modulated its microenvironment. Our typical samples, e.g. complex DNA-origami assemblies, metasurfaces, hydrogels, cells and cellular mimics as well as their constituting building block, e.g. DNA-origamis, biomolecules, TOM (translocase of the outer membrane) complexes, proteins, polymer and metal nanostructures, have to be imaged with nanometer spatial resolution under controllable (physiologically relevant) conditions. In contrast to electron and optical microscopy, atomic force microscopy, which is state of the art and a well-established technology in nanoscience and cell biology, offers such functionalities. Additionally, the requested AFM should provide a variety of operation modes enabling high-resolution imaging, high-speed imaging (at least 7 frames per second), AFM-tip-based SECM (at least sub-100 nm spatial resolution) and force spectroscopy for nanomechanical characterization. It should operate in tip-scanning configuration and be compatible with inverted confocal microscopes. An AFM providing these versatile functionalities is currently not available at the University of Stuttgart. We therefore heavily rely on the acquisition of such a versatile tool to gain new insight into the assembly and functional dynamics of (hybrid) DNA-based nanoarchitectures and conducting-polymer-based metasurfaces, the transport processes across biological membranes, the hydrogel-controlled biological cellular responses as well as epithelial cells and tissue physiology.