The nano-scale structure of cytoskeletal biopolymers as well as sophisticated superstructures determine the versatile cellular shapes and specific mechanical properties. One example is keratin intermediate filaments in epithelial cells, which form thick bundles that can further organize in a crosslinked network. To study the native structure of keratin bundles in whole cells, high-resolution techniques are required, which do at the same time achieve high penetration depths. We employ scanning x-ray diffraction using a nano-focused x-ray beam to study the structure of keratin in freeze-dried eukaryotic cells. By scanning the sample through the beam we obtain x-ray dark-field images with a resolution of the order of the beam size, which clearly show the keratin network. Each individual diffraction pattern is further analyzed to yield insight into the local sample structure, which allows us to determine the local structure orientation. Due to the small beam size we access the structure in a small sample volume without performing the ensemble average over one complete cell.

Domain wall movement assisted transport of particles: exchange-biased samples with designed stripe-domains show strong stray fields and an asymmetric magnetization reversal. Using these characteristics superparamagnetic particles can be trapped and transported directly on the sample over large-scale areas. High particle velocities, small external fields, and automatically reduced particle clustering allow broad applicability of this transport method.

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During the past decade, piezo-resistive cantilever type silicon microprobes for high-speed roughness measurements inside high-aspect-ratio microstructures, like injection nozzles or critical gas nozzles have been developed. This article summarizes their metrological properties for fast roughness and shape measurements including noise, damping, tip form, tip wear, and probing forces and presents the first results on the measurement of mechanical surface parameters. Due to the small mass of the cantilever microprobes, roughness measurements at very high traverse speeds up to 15 mm/s are possible. At these high scanning speeds, considerable wear of the integrated silicon tips was observed in the past. In this paper, a new tip-testing artefact with rectangular grooves of different width was used to measure this wear and to measure the tip shape, which is needed for morphological filtering of the measured profiles and, thus, for accurate form measurements. To reduce tip wear, the integrated silicon tips were replaced by low-wear spherical diamond tips of a 2 µm radius. Currently, a compact microprobe device with an integrated feed-unit is being developed for high-speed roughness measurements on manufacturing machines. First measurements on sinusoidal artefacts were carried out successfully. Moreover, the first measurements of the elastic modulus of a polymer surface applying the contact resonance measurement principle are presented, which indicates the high potential of these microprobes for simultaneous high-speed roughness and mechanical parameter measurements.

This work reports on the nanomechanical metrology of vertically aligned gallium nitride micropillar arrays with high homogeneity and well‐controlled geometry. The GaN micro‐building blocks are top‐down fabricated by combining photolithography, inductively coupled plasma dry reactive ion etching (ICP‐DRIE) with SF6/H2 gases, and post‐wet chemical etching treatment by a KOH‐based solution. A nanoindenter with a three‐sided pyramid Berkovich tip is employed to precisely measure the mechanical properties of the GaN micropillars directly from their top surfaces, hence an additional preparatory work to transfer them on a foreign substrate is not necessary. From the obtained experimental results, the insight of the indentation pop‐in phenomenon on the micropillars is carefully investigated. Besides, a confocal laser scanning microscope (CLSM) and an atomic force microscope (AFM) are utilized to confirm the high homogeneity of the micropillar arrays before indentation and to characterize the morphologies of their top surfaces after stress relaxation, respectively. Therefore, the obtained experimental results can be employed as the prior knowledge to be compared with the bulk counterparts, in which the GaN micropillars can be further developed for mechanical force sensors, since the performed measurement techniques have provided the existent mechanical circumstance of the microstructures when a vertical force is applied.