@article{WeiglBlumSanchoetal.2022, author = {Weigl, Franziska and Blum, Carina and Sancho, Ana and Groll, J{\"u}rgen}, title = {Correlative Analysis of Intra- Versus Extracellular Cell Detachment Events via the Alignment of Optical Imaging and Detachment Force Quantification}, series = {Advanced Materials Technologies}, volume = {7}, journal = {Advanced Materials Technologies}, number = {11}, issn = {2365-709X}, doi = {10.1002/admt.202200195}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-318544}, year = {2022}, abstract = {In recent decades, hybrid characterization systems have become pillars in the study of cellular biomechanics. Especially, Atomic Force Microscopy (AFM) is combined with a variety of optical microscopy techniques to discover new aspects of cell adhesion. AFM, however, is limited to the early-stage of cell adhesion, so that the forces of mature cell contacts cannot be addressed. Even though the invention of Fluidic Force Microscopy (FluidFM) overcomes these limitations by combining the precise force-control of AFM with microfluidics, the correlative investigation of detachment forces arising from spread mammalian cells has been barely achieved. Here, a novel multifunctional device integrating Fluorescence Microscopy (FL) into FluidFM technology (FL-FluidFM) is introduced, enabling real-time optical tracking of entire cell detachment processes in parallel to the undisturbed acquisition of force-distance curves. This setup, thus, allows for entailing two pieces of information at once. As proof-of-principle experiment, this method is applied to fluorescently labeled rat embryonic fibroblast (REF52) cells, demonstrating a precise matching between identified force-jumps and visualized cellular unbinding steps. This study, thus, presents a novel characterization tool for the correlated evaluation of mature cell adhesion, which has great relevance, for instance, in the development of biomaterials or the fight against diseases such as cancer.}, language = {en} } @article{RymaGencNadernezhadetal.2022, author = {Ryma, Matthias and Gen{\c{c}}, Hatice and Nadernezhad, Ali and Paulus, Ilona and Schneidereit, Dominik and Friedrich, Oliver and Andelovic, Kristina and Lyer, Stefan and Alexiou, Christoph and Cicha, Iwona and Groll, J{\"u}rgen}, title = {A Print-and-Fuse Strategy for Sacrificial Filaments Enables Biomimetically Structured Perfusable Microvascular Networks with Functional Endothelium Inside 3D Hydrogels}, series = {Advanced Materials}, volume = {34}, journal = {Advanced Materials}, number = {28}, doi = {10.1002/adma.202200653}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-318532}, year = {2022}, abstract = {A facile and flexible approach for the integration of biomimetically branched microvasculature within bulk hydrogels is presented. For this, sacrificial scaffolds of thermoresponsive poly(2-cyclopropyl-2-oxazoline) (PcycloPrOx) are created using melt electrowriting (MEW) in an optimized and predictable way and subsequently placed into a customized bioreactor system, which is then filled with a hydrogel precursor solution. The aqueous environment above the lower critical solution temperature (LCST) of PcycloPrOx at 25 °C swells the polymer without dissolving it, resulting in fusion of filaments that are deposited onto each other (print-and-fuse approach). Accordingly, an adequate printing pathway design results in generating physiological-like branchings and channel volumes that approximate Murray's law in the geometrical ratio between parent and daughter vessels. After gel formation, a temperature decrease below the LCST produces interconnected microchannels with distinct inlet and outlet regions. Initial placement of the sacrificial scaffolds in the bioreactors in a pre-defined manner directly yields perfusable structures via leakage-free fluid connections in a reproducible one-step procedure. Using this approach, rapid formation of a tight and biologically functional endothelial layer, as assessed not only through fluorescent dye diffusion, but also by tumor necrosis factor alpha (TNF-α) stimulation, is obtained within three days.}, language = {en} } @article{PereiraTrivanovićStahlhutetal.2022, author = {Pereira, Ana Rita and Trivanović, Drenka and Stahlhut, Philipp and Rudert, Maximilian and Groll, J{\"u}rgen and Herrmann, Marietta}, title = {Preservation of the na{\"i}ve features of mesenchymal stromal cells in vitro: Comparison of cell- and bone-derived decellularized extracellular matrix}, series = {Journal of Tissue Engineering}, volume = {13}, journal = {Journal of Tissue Engineering}, doi = {10.1177/20417314221074453}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-268835}, pages = {1-12}, year = {2022}, abstract = {The fate and behavior of bone marrow mesenchymal stem/stromal cells (BM-MSC) is bidirectionally influenced by their microenvironment, the stem cell niche, where a magnitude of biochemical and physical cues communicate in an extremely orchestrated way. It is known that simplified 2D in vitro systems for BM-MSC culture do not represent their na{\"i}ve physiological environment. Here, we developed four different 2D cell-based decellularized matrices (dECM) and a 3D decellularized human trabecular-bone scaffold (dBone) to evaluate BM-MSC behavior. The obtained cell-derived matrices provided a reliable tool for cell shape-based analyses of typical features associated with osteogenic differentiation at high-throughput level. On the other hand, exploratory proteomics analysis identified native bone-specific proteins selectively expressed in dBone but not in dECM models. Together with its architectural complexity, the physico-chemical properties of dBone triggered the upregulation of stemness associated genes and niche-related protein expression, proving in vitro conservation of the na{\"i}ve features of BM-MSC.}, language = {en} } @article{HauptsteinForsterNadernezhadetal.2022, author = {Hauptstein, Julia and Forster, Leonard and Nadernezhad, Ali and Horder, Hannes and Stahlhut, Philipp and Groll, J{\"u}rgen and Blunk, Torsten and Teßmar, J{\"o}rg}, title = {Bioink Platform Utilizing Dual-Stage Crosslinking of Hyaluronic Acid Tailored for Chondrogenic Differentiation of Mesenchymal Stromal Cells}, series = {Macromolecular Bioscience}, volume = {22}, journal = {Macromolecular Bioscience}, number = {2}, doi = {10.1002/mabi.202100331}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257556}, pages = {2100331}, year = {2022}, abstract = {3D bioprinting often involves application of highly concentrated polymeric bioinks to enable fabrication of stable cell-hydrogel constructs, although poor cell survival, compromised stem cell differentiation, and an inhomogeneous distribution of newly produced extracellular matrix (ECM) are frequently observed. Therefore, this study presents a bioink platform using a new versatile dual-stage crosslinking approach based on thiolated hyaluronic acid (HA-SH), which not only provides stand-alone 3D printability but also facilitates effective chondrogenic differentiation of mesenchymal stromal cells. A range of HA-SH with different molecular weights is synthesized and crosslinked with acrylated (PEG-diacryl) and allylated (PEG-diallyl) polyethylene glycol in a two-step reaction scheme. The initial Michael addition is used to achieve ink printability, followed by UV-mediated thiol-ene reaction to stabilize the printed bioink for long-term cell culture. Bioinks with high molecular weight HA-SH (>200 kDa) require comparably low polymer content to facilitate bioprinting. This leads to superior quality of cartilaginous constructs which possess a coherent ECM and a strongly increased stiffness of long-term cultured constructs. The dual-stage system may serve as an example to design platforms using two independent crosslinking reactions at one functional group, which allows adjusting printability as well as material and biological properties of bioinks.}, language = {en} } @article{HauptsteinForsterNadernezhadetal.2022, author = {Hauptstein, Julia and Forster, Leonard and Nadernezhad, Ali and Groll, J{\"u}rgen and Teßmar, J{\"o}rg and Blunk, Torsten}, title = {Tethered TGF-β1 in a hyaluronic acid-based bioink for bioprinting cartilaginous tissues}, series = {International Journal of Molecular Sciences}, volume = {23}, journal = {International Journal of Molecular Sciences}, number = {2}, issn = {1422-0067}, doi = {10.3390/ijms23020924}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-284239}, year = {2022}, abstract = {In 3D bioprinting for cartilage regeneration, bioinks that support chondrogenic development are of key importance. Growth factors covalently bound in non-printable hydrogels have been shown to effectively promote chondrogenesis. However, studies that investigate the functionality of tethered growth factors within 3D printable bioinks are still lacking. Therefore, in this study, we established a dual-stage crosslinked hyaluronic acid-based bioink that enabled covalent tethering of transforming growth factor-beta 1 (TGF-β1). Bone marrow-derived mesenchymal stromal cells (MSCs) were cultured over three weeks in vitro, and chondrogenic differentiation of MSCs within bioink constructs with tethered TGF-β1 was markedly enhanced, as compared to constructs with non-covalently incorporated TGF-β1. This was substantiated with regard to early TGF-β1 signaling, chondrogenic gene expression, qualitative and quantitative ECM deposition and distribution, and resulting construct stiffness. Furthermore, it was successfully demonstrated, in a comparative analysis of cast and printed bioinks, that covalently tethered TGF-β1 maintained its functionality after 3D printing. Taken together, the presented ink composition enabled the generation of high-quality cartilaginous tissues without the need for continuous exogenous growth factor supply and, thus, bears great potential for future investigation towards cartilage regeneration. Furthermore, growth factor tethering within bioinks, potentially leading to superior tissue development, may also be explored for other biofabrication applications.}, language = {en} } @article{BrandForsterBoecketal.2022, author = {Brand, Jessica S. and Forster, Leonard and B{\"o}ck, Thomas and Stahlhut, Philipp and Teßmar, J{\"o}rg and Groll, J{\"u}rgen and Albrecht, Krystyna}, title = {Covalently Cross-Linked Pig Gastric Mucin Hydrogels Prepared by Radical-Based Chain-Growth and Thiol-ene Mechanisms}, series = {Macromolecular Bioscience}, volume = {22}, journal = {Macromolecular Bioscience}, number = {4}, doi = {10.1002/mabi.202100274}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-318453}, year = {2022}, abstract = {Mucin, a high molecular mass hydrophilic glycoprotein, is the main component of mucus that coats every wet epithelium in animals. It is thus intrinsically biocompatible, and with its protein backbone and the o-glycosidic bound oligosaccharides, it contains a plethora of functional groups which can be used for further chemical modifications. Here, chain-growth and step-growth (thiol-ene) free-radical cross-linked hydrogels prepared from commercially available pig gastric mucin (PGM) are introduced and compared as cost-efficient and easily accessible alternative to the more broadly applied bovine submaxillary gland mucin. For this, PGM is functionalized with photoreactive acrylate groups or allyl ether moieties, respectively. Whereas homopolymerization of acrylate-functionalized polymers is performed, for thiol-ene cross-linking, the allyl-ether-functionalized PGM is cross-linked with thiol-functionalized hyaluronic acid. Morphology, mechanical properties, and cell compatibility of both kinds of PGM hydrogels are characterized and compared. Furthermore, the biocompatibility of these hydrogels can be evaluated in cell culture experiments.}, language = {en} }