Berlin 2018 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 27: Poster Session I

MM 27.31: Poster

Tuesday, March 13, 2018, 18:30–19:45, Poster E

Subsurface Imaging of magnetic nanoparticles and measurement of nanomechanical properties of polymers and biological materials by bimodal atomic force microscopy. — •Lukas Stühn and Christian Dietz — Technische Universität Darmstadt, Darmstadt, Deutschland

We aim to observe the intrusion process of nanoparticles into human cells by bimodal frequency-modulated atomic force microscopy. To this end, a magnetic tip of an atomic force microscope is used to simultaneously detect the local mechanical properties of human HUVEC-cells and the subsurface locations of superparamagnetic ferritin nanoparticles.

We show that the mechanical characterization of biologic and polymeric matter is possible by the use of low-noise small cantilevers and photothermal excitation of the cantilever. To detect magnetic properties in a liquid environment, we increased the cantilever's oscillation amplitude several times using a backside coating of colloidal graphite. By embedding ferritin nanoparticles into a polymer-film, we studied the depth limits of the subsurface detection. High-resolution measurements of ferritin nanoparticles in liquids of different pH-values provided a first indication of the stability and organization of the protein shell. Moreover, we present images of human HUVEC-cells acquired by dynamic force microscopy.