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Author: Rose, Jonas C. × Subject: Anisotropy ×

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Now showing 1 - 2 of 2
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    Predicting the orientation of magnetic microgel rods for soft anisotropic biomimetic hydrogels
    (Cambridge : RSC Publ., 2020) Rose, Jonas C.; Fölster, Maaike; Kivilip, Lukas; Gerardo-Nava, Jose L.; Jaekel, Esther E.; Gehlen, David B.; Rohlfs, Wilko; De Laporte, Laura
    Living multicellular organisms comprise a high degree of soft anisotropic tissues but the development of controlled artificial assembly processes to mimic them remains challenging. Therefore, injectable, polymeric, magneto-responsive microgel rods are fabricated to orient within a low magnetic field. The incorporated superparamagnetic nanoparticles induce local dipole moments, resulting in a total magnetic torque that endows microgels with different structural, mechanical, and biochemical properties. In this report, a predictive macroscopic model based on an ellipsoidal element dispersed in a Newtonian fluid is adjusted using experimental data, which enables the prediction of the orientation rate and the required magnetic field strength for various microgel design parameters and fluid viscosities. The ordered microgels are fixed by crosslinking of a surrounding hydrogel, and can be employed for a wide variety of applications where anisotropic composite hydrogels play a crucial role; for instance as adaptive materials or in biomedical applications, wherein the model predictions can reduce animal experiments. © 2019 The Royal Society of Chemistry.
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    Biofunctionalized aligned microgels provide 3D cell guidance to mimic complex tissue matrices
    (Amsterdam [u.a.] : Elsevier, 2018) Rose, Jonas C.; Gehlen, David B.; Haraszti, Tamás; Köhler, Jens; Licht, Christopher J.; De Laporte, Laura
    Natural healing is based on highly orchestrated processes, in which the extracellular matrix plays a key role. To resemble the native cell environment, we introduce an artificial extracellular matrix (aECM) with the capability to template hierarchical and anisotropic structures in situ, allowing a minimally-invasive application via injection. Synthetic, magnetically responsive, rod-shaped microgels are locally aligned and fixed by a biocompatible surrounding hydrogel, creating a hybrid anisotropic hydrogel (Anisogel), of which the physical, mechanical, and chemical properties can be tailored. The microgels are rendered cell-adhesive with GRGDS and incorporated either inside a cell-adhesive fibrin or bioinert poly(ethylene glycol) hydrogel to strongly interact with fibroblasts. GRGDS-modified microgels inside a fibrin-based Anisogel enhance fibroblast alignment and lead to a reduction in fibronectin production, indicating successful replacement of structural proteins. In addition, YAP-translocation to the nucleus increases with the concentration of microgels, indicating cellular sensing of the overall anisotropic mechanical properties of the Anisogel. For bioinert surrounding PEG hydrogels, GRGDS-microgels are required to support cell proliferation and fibronectin production. In contrast to fibroblasts, primary nerve growth is not significantly affected by the biomodification of the microgels. In conclusion, this approach opens new opportunities towards advanced and complex aECMs for tissue regeneration.