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Author: Omidinia-Anarkoli, Abdolrahman × Start date: 2018 × Type: Text × Publisher: Weinheim : Wiley-VCH ×

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    How Much Physical Guidance is Needed to Orient Growing Axons in 3D Hydrogels?
    (Weinheim : Wiley-VCH, 2020) Rose, Jonas C.; Gehlen, David B.; Omidinia-Anarkoli, Abdolrahman; Fölster, Maaike; Haraszti, Tamás; Jaekel, Esther E.; De Laporte, Laura
    Directing cells is essential to organize multi-cellular organisms that are built up from subunits executing specific tasks. This guidance requires a precisely controlled symphony of biochemical, mechanical, and structural signals. While many guiding mechanisms focus on 2D structural patterns or 3D biochemical gradients, injectable material platforms that elucidate how cellular processes are triggered by defined 3D physical guiding cues are still lacking but crucial for the repair of soft tissues. Herein, a recently developed anisotropic injectable hybrid hydrogel (Anisogel) contains rod-shaped microgels that orient in situ by a magnetic field and has propelled studying 3D cell guidance. Here, the Anisogel is used to investigate the dependence of axonal guidance on microgel dimensions, aspect ratio, and distance. While large microgels result in high material anisotropy, they significantly reduce neurite outgrowth and thus the guidance efficiency. Narrow and long microgels enable strong axonal guidance with maximal outgrowth including cell sensing over distances of tens of micrometers in 3D. Moreover, nerve cells decide to orient inside the Anisogel within the first three days, followed by strengthening of the alignment, which goes along with oriented fibronectin deposition. These findings demonstrate the potential of the Anisogel to tune structural and mechanical parameters for specific applications. © 2020 The Authors. Published by Wiley-VCH GmbH
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    Controlling Structure with Injectable Biomaterials to Better Mimic Tissue Heterogeneity and Anisotropy
    (Weinheim : Wiley-VCH, 2021) Babu, Susan; Albertino, Filippo; Omidinia-Anarkoli, Abdolrahman; De Laporte, Laura
    Tissue regeneration of sensitive tissues calls for injectable scaffolds, which are minimally invasive and offer minimal damage to the native tissues. However, most of these systems are inherently isotropic and do not mimic the complex hierarchically ordered nature of the native extracellular matrices. This review focuses on the different approaches developed in the past decade to bring in some form of anisotropy to the conventional injectable tissue regenerative matrices. These approaches include introduction of macroporosity, in vivo pattering to present biomolecules in a spatially and temporally controlled manner, availability of aligned domains by means of self-assembly or oriented injectable components, and in vivo bioprinting to obtain structures with features of high resolution that resembles native tissues. Toward the end of the review, different techniques to produce building blocks for the fabrication of heterogeneous injectable scaffolds are discussed. The advantages and shortcomings of each approach are discussed in detail with ideas to improve the functionality and versatility of the building blocks. © 2021 The Authors. Advanced Healthcare Materials published by Wiley-VCH GmbH
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    Granular Cellulose Nanofibril Hydrogel Scaffolds for 3D Cell Cultivation
    (Weinheim : Wiley-VCH, 2020) Gehlen, David B.; Jürgens, Niklas; Omidinia-Anarkoli, Abdolrahman; Haraszti, Tamás; George, Julian; Walther, Andreas; Ye, Hua; De Laporte, Laura
    The replacement of diseased and damaged organs remains an challenge in modern medicine. However, through the use of tissue engineering techniques, it may soon be possible to (re)generate tissues and organs using artificial scaffolds. For example, hydrogel networks made from hydrophilic precursor solutions can replicate many properties found in the natural extracellular matrix (ECM) but often lack the dynamic nature of the ECM, as many covalently crosslinked hydrogels possess elastic and static networks with nanoscale pores hindering cell migration without being degradable. To overcome this, macroporous colloidal hydrogels can be prepared to facilitate cell infiltration. Here, an easy method is presented to fabricate granular cellulose nanofibril hydrogel (CNF) scaffolds as porous networks for 3D cell cultivation. CNF is an abundant natural and highly biocompatible material that supports cell adhesion. Granular CNF scaffolds are generated by pre-crosslinking CNF using calcium and subsequently pressing the gel through micrometer-sized nylon meshes. The granular solution is mixed with fibroblasts and crosslinked with cell culture medium. The obtained granular CNF scaffold is significantly softer and enables well-distributed fibroblast growth. This cost-effective material combined with this efficient and facile fabrication technique allows for 3D cell cultivation in an upscalable manner. © 2020 The Authors. Published by Wiley-VCH GmbH