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    Magnetic measurement methods to probe nanoparticle–matrix interactions
    (Berlin : de Gruyter, 2021) Liebl, Maik; Eberbeck, Dietmar; Coene, Annelies; Leliaert, Jonathan; Jauch, Philine; Kruteva, Margarita; Fruhner, Lisa; Barnsley, Lester; Mayr, Stefan G.; Wiekhorst, Frank
    Magnetic nanoparticles (MNPs) are key elements in several biomedical applications, e.g., in cancer therapy. Here, the MNPs are remotely manipulated by magnetic fields from outside the body to deliver drugs or generate heat in tumor tissue. The efficiency and success of these approaches strongly depend on the spatial distribution and quantity of MNPs inside a body and interactions of the particles with the biological matrix. These include dynamic processes of the MNPs in the organism such as binding kinetics, cellular uptake, passage through cell barriers, heat induction and flow. While magnetic measurement methods have been applied so far to resolve the location and quantity of MNPs for therapy monitoring, these methods can be advanced to additionally access these particle–matrix interactions. By this, the MNPs can further be utilized as probes for the physical properties of their molecular environment. In this review, we first investigate the impact of nanoparticle–matrix interactions on magnetic measurements in selected experiments. With these results, we then advanced the imaging modalities magnetorelaxometry imaging and magnetic microsphere tracking to spatially resolve particle–matrix interactions.
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    Collagen-iron oxide nanoparticle based ferrogel: Large reversible magnetostrains with potential for bioactuation
    (Bristol : IOP Publishing, 2020) Jauch, Philine; Weidner, Andreas; Riedel, Stefanie; Wilharm, Nils; Dutz, Silvio; Mayr, Stefan G.
    Smart materials such as stimuli responsive polymeric hydrogels offer unique possibilities for tissue engineering and regenerative medicine. As, however, most synthetic polymer systems and their degradation products lack complete biocompatibility and biodegradability, this study aims to synthesize a highly magnetic responsive hydrogel, based on the abundant natural biopolymer collagen. As the main component of vertebratal extracellular matrix, it reveals excellent biocompatibility. In combination with incorporated magnetic iron oxide nanoparticles, a novel smart nano-bio-ferrogel can be designed. While retaining its basic biophysical properties and interaction with living cells, this collagen-nanoparticle hydrogel can be compressed to 38% of its original size and recovers to 95% in suitable magnetic fields. Besides the phenomenology of this scenario, the underlying physical scenarios are also discussed within the framework of network models. The observed reversible peak strains as large as 150% open up possibilities for the fields of biomedical actuation, soft robotics and beyond. © 2020 The Author(s). Published by IOP Publishing Ltd