TY - JOUR A1 - Weissenberger, Manuel A1 - Weissenberger, Manuela H. A1 - Wagenbrenner, Mike A1 - Heinz, Tizian A1 - Reboredo, Jenny A1 - Holzapfel, Boris M. A1 - Rudert, Maximilian A1 - Groll, Jürgen A1 - Evans, Christopher H. A1 - Steinert, Andre F. T1 - Different types of cartilage neotissue fabricated from collagen hydrogels and mesenchymal stromal cells via SOX9, TGFB1 or BMP2 gene transfer JF - PLoS One N2 - Objective As native cartilage consists of different phenotypical zones, this study aims to fabricate different types of neocartilage constructs from collagen hydrogels and human mesenchymal stromal cells (MSCs) genetically modified to express different chondrogenic factors. Design Human MSCs derived from bone-marrow of osteoarthritis (OA) hips were genetically modified using adenoviral vectors encoding sex-determining region Y-type high-mobility-group-box (SOX)9,transforming growth factor beta (TGFB) 1or bone morphogenetic protein (BMP) 2cDNA, placed in type I collagen hydrogels and maintained in serum-free chondrogenic media for three weeks. Control constructs contained unmodified MSCs or MSCs expressing GFP. The respective constructs were analyzed histologically, immunohistochemically, biochemically, and by qRT-PCR for chondrogenesis and hypertrophy. Results Chondrogenesis in MSCs was consistently and strongly induced in collagen I hydrogels by the transgenesSOX9,TGFB1andBMP2as evidenced by positive staining for proteoglycans, chondroitin-4-sulfate (CS4) and collagen (COL) type II, increased levels of glycosaminoglycan (GAG) synthesis, and expression of mRNAs associated with chondrogenesis. The control groups were entirely non-chondrogenic. The levels of hypertrophy, as judged by expression of alkaline phosphatase (ALP) and COL X on both the protein and mRNA levels revealed different stages of hypertrophy within the chondrogenic groups (BMP2>TGFB1>SOX9). Conclusions Different types of neocartilage with varying levels of hypertrophy could be generated from human MSCs in collagen hydrogels by transfer of genes encoding the chondrogenic factorsSOX9,TGFB1andBMP2. This technology may be harnessed for regeneration of specific zones of native cartilage upon damage. KW - stem cells KW - in vitro KW - chondrogenic differentiation KW - repair KW - chondrocytes KW - transplantation KW - stimulation KW - scaffolds KW - defects KW - therapy Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230494 VL - 15 IS - 8 ER - TY - JOUR A1 - Weis, Matthias A1 - Shan, Junwen A1 - Kuhlmann, Matthias A1 - Jungst, Tomasz A1 - Tessmar, Jörg A1 - Groll, Jürgen T1 - Evaluation of hydrogels based on oxidized hyaluronic acid for bioprinting JF - Gels N2 - In this study, we evaluate hydrogels based on oxidized hyaluronic acid, cross-linked with adipic acid dihydrazide, for their suitability as bioinks for 3D bioprinting. Aldehyde containing hyaluronic acid (AHA) is synthesized and cross-linked via Schiff Base chemistry with bifunctional adipic acid dihydrazide (ADH) to form a mechanically stable hydrogel with good printability. Mechanical and rheological properties of the printed and casted hydrogels are tunable depending on the concentrations of AHA and ADH cross-linkers. KW - biofabrication KW - bioprinting KW - hyaluronic acid Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-197600 SN - 2310-2861 VL - 4 IS - 4 ER - TY - JOUR A1 - Weigl, Franziska A1 - Blum, Carina A1 - Sancho, Ana A1 - Groll, Jürgen T1 - Correlative Analysis of Intra– Versus Extracellular Cell Detachment Events via the Alignment of Optical Imaging and Detachment Force Quantification JF - Advanced Materials Technologies N2 - 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. KW - Fluorescence Microscopy KW - FluidFM technology KW - detachment force quantification Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318544 SN - 2365-709X VL - 7 IS - 11 ER - TY - JOUR A1 - Tylek, Tina A1 - Schilling, Tatjana A1 - Schlegelmilch, Katrin A1 - Ries, Maximilian A1 - Rudert, Maximilian A1 - Jakob, Franz A1 - Groll, Jürgen T1 - Platelet lysate outperforms FCS and human serum for co-culture of primary human macrophages and hMSCs JF - Scientific Reports N2 - In vitro co-cultures of different primary human cell types are pivotal for the testing and evaluation of biomaterials under conditions that are closer to the human in vivo situation. Especially co-cultures of macrophages and mesenchymal stem cells (MSCs) are of interest, as they are both present and involved in tissue regeneration and inflammatory reactions and play crucial roles in the immediate inflammatory reactions and the onset of regenerative processes, thus reflecting the decisive early phase of biomaterial contact with the host. A co-culture system of these cell types might thus allow for the assessment of the biocompatibility of biomaterials. The establishment of such a co-culture is challenging due to the different in vitro cell culture conditions. For human macrophages, medium is usually supplemented with human serum (hS), whereas hMSC culture is mostly performed using fetal calf serum (FCS), and these conditions are disadvantageous for the respective other cell type. We demonstrate that human platelet lysate (hPL) can replace hS in macrophage cultivation and appears to be the best option for co-cultivation of human macrophages with hMSCs. In contrast to FCS and hS, hPL maintained the phenotype of both cell types, comparable to that of their respective standard culture serum, as well as the percentage of each cell population. Moreover, the expression profile and phagocytosis activity of macrophages was similar to hS. KW - biomaterials – cells KW - tissue engineering Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229174 VL - 9 ER - TY - JOUR A1 - Tylek, Tina A1 - Blum, Carina A1 - Hrynevich, Andrei A1 - Schlegelmilch, Katrin A1 - Schilling, Tatjana A1 - Dalton, Paul D A1 - Groll, Jürgen T1 - Precisely defined fiber scaffolds with 40 μm porosity induce elongation driven M2-like polarization of human macrophages JF - Biofabrication N2 - Macrophages are key players of the innate immune system that can roughly be divided into the pro-inflammatory M1 type and the anti-inflammatory, pro-healing M2 type. While a transient initial pro-inflammatory state is helpful, a prolonged inflammation deteriorates a proper healing and subsequent regeneration. One promising strategy to drive macrophage polarization by biomaterials is precise control over biomaterial geometry. For regenerative approaches, it is of particular interest to identify geometrical parameters that direct human macrophage polarization. For this purpose, we advanced melt electrowriting (MEW) towards the fabrication of fibrous scaffolds with box-shaped pores and precise inter-fiber spacing from 100 μm down to only 40 μm. These scaffolds facilitate primary human macrophage elongation accompanied by differentiation towards the M2 type, which was most pronounced for the smallest pore size of 40 μm. These new findings can be important in helping to design new biomaterials with an enhanced positive impact on tissue regeneration. KW - cell elongation KW - human macrophages KW - melt electrowriting (MEW) KW - macrophage polarization KW - 3D scaffolds Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-254012 VL - 12 IS - 2 ER - TY - JOUR A1 - Sun, Wei A1 - Starly, Binil A1 - Daly, Andrew C A1 - Burdick, Jason A A1 - Groll, Jürgen A1 - Skeldon, Gregor A1 - Shu, Wenmiao A1 - Sakai, Yasuyuki A1 - Shinohara, Marie A1 - Nishikawa, Masaki A1 - Jang, Jinah A1 - Cho, Dong-Woo A1 - Nie, Minghao A1 - Takeuchi, Shoji A1 - Ostrovidov, Serge A1 - Khademhosseini, Ali A1 - Kamm, Roger D A1 - Mironov, Vladimir A1 - Moroni, Lorenzo A1 - Ozbolat, Ibrahim T T1 - The bioprinting roadmap JF - Biofabrication N2 - This bioprinting roadmap features salient advances in selected applications of the technique and highlights the status of current developments and challenges, as well as envisioned advances in science and technology, to address the challenges to the young and evolving technique. The topics covered in this roadmap encompass the broad spectrum of bioprinting; from cell expansion and novel bioink development to cell/stem cell printing, from organoid-based tissue organization to bioprinting of human-scale tissue structures, and from building cell/tissue/organ-on-a-chip to biomanufacturing of multicellular engineered living systems. The emerging application of printing-in-space and an overview of bioprinting technologies are also included in this roadmap. Due to the rapid pace of methodological advancements in bioprinting techniques and wide-ranging applications, the direction in which the field should advance is not immediately clear. This bioprinting roadmap addresses this unmet need by providing a comprehensive summary and recommendations useful to experienced researchers and newcomers to the field. KW - biofabrication KW - bioprinting KW - cell printing KW - biological models KW - disease models KW - organoids KW - organ-on-a-chip Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-254027 VL - 12 IS - 2 ER - TY - JOUR A1 - Stuckensen, Kai A1 - Lamo-Espinosa, José M. A1 - Muiños-López, Emma A1 - Ripalda-Cemboráin, Purificación A1 - López-Martínez, Tania A1 - Iglesias, Elena A1 - Abizanda, Gloria A1 - Andreu, Ion A1 - Flandes-Iparraguirre, María A1 - Pons-Villanueva, Juan A1 - Elizalde, Reyes A1 - Nickel, Joachim A1 - Ewald, Andrea A1 - Gbureck, Uwe A1 - Prósper, Felipe A1 - Groll, Jürgen A1 - Granero-Moltó, Froilán T1 - Anisotropic cryostructured collagen scaffolds for efficient delivery of RhBMP−2 and enhanced bone regeneration JF - Materials N2 - In the treatment of bone non-unions, an alternative to bone autografts is the use of bone morphogenetic proteins (BMPs), e.g., BMP–2, BMP–7, with powerful osteoinductive and osteogenic properties. In clinical settings, these osteogenic factors are applied using absorbable collagen sponges for local controlled delivery. Major side effects of this strategy are derived from the supraphysiological doses of BMPs needed, which may induce ectopic bone formation, chronic inflammation, and excessive bone resorption. In order to increase the efficiency of the delivered BMPs, we designed cryostructured collagen scaffolds functionalized with hydroxyapatite, mimicking the structure of cortical bone (aligned porosity, anisotropic) or trabecular bone (random distributed porosity, isotropic). We hypothesize that an anisotropic structure would enhance the osteoconductive properties of the scaffolds by increasing the regenerative performance of the provided rhBMP–2. In vitro, both scaffolds presented similar mechanical properties, rhBMP–2 retention and delivery capacity, as well as scaffold degradation time. In vivo, anisotropic scaffolds demonstrated better bone regeneration capabilities in a rat femoral critical-size defect model by increasing the defect bridging. In conclusion, anisotropic cryostructured collagen scaffolds improve bone regeneration by increasing the efficiency of rhBMP–2 mediated bone healing. KW - rhBMP–2 KW - collagen sponge KW - cryostructured scaffolds KW - bone critical size defect Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-195966 SN - 1996-1944 VL - 12 IS - 19 ER - TY - JOUR A1 - Shan, Junwen A1 - Böck, Thomas A1 - Keller, Thorsten A1 - Forster, Leonard A1 - Blunk, Torsten A1 - Groll, Jürgen A1 - Teßmar, Jörg T1 - TEMPO/TCC as a Chemo Selective Alternative for the Oxidation of Hyaluronic Acid JF - Molecules N2 - Hyaluronic acid (HA)-based hydrogels are very commonly applied as cell carriers for different approaches in regenerative medicine. HA itself is a well-studied biomolecule that originates from the physiological extracellular matrix (ECM) of mammalians and, due to its acidic polysaccharide structure, offers many different possibilities for suitable chemical modifications which are necessary to control, for example, network formation. Most of these chemical modifications are performed using the free acid function of the polymer and, additionally, lead to an undesirable breakdown of the biopolymer’s backbone. An alternative modification of the vicinal diol of the glucuronic acid is oxidation with sodium periodate to generate dialdehydes via a ring opening mechanism that can subsequently be further modified or crosslinked via Schiff base chemistry. Since this oxidation causes a structural destruction of the polysaccharide backbone, it was our intention to study a novel synthesis protocol frequently applied to selectively oxidize the C6 hydroxyl group of saccharides. On the basis of this TEMPO/TCC oxidation, we studied an alternative hydrogel platform based on oxidized HA crosslinked using adipic acid dihydrazide as the crosslinker. KW - hyaluronic acid KW - oxidation KW - hydrogel formation KW - Schiff base chemistry Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-248362 SN - 1420-3049 VL - 26 IS - 19 ER - TY - JOUR A1 - Seifert, Annika A1 - Gruber, Julia A1 - Gbureck, Uwe A1 - Groll, Jürgen T1 - Morphological control of freeze‐structured scaffolds by selective temperature and material control in the ice‐templating process JF - Advanced Engineering Materials N2 - Herein, it is aimed to highlight the importance of the process parameter choice during directional solidification of polymer solutions, as they have a significant influence on the pore structure and orientation. Biopolymer solutions (alginate and chitosan) are directionally frozen, while systematically varying parameters such as the external temperature gradient, the temperature of the overall system, and the temperatures of the cooling surfaces. In addition, the effect of material properties such as molecular weight, solution concentration, or viscosity on the sample morphology is investigated. By selecting appropriate temperature gradients and cooling surface temperatures, aligned pores ranging in size between (50 ± 22) μm and (144 ± 56) μm are observed in the alginate samples, whereas the pore orientation is influenced by altering the external temperature gradient. As this gradient increases, the pores are increasingly oriented perpendicular to the sample surface. This is also observed in the chitosan samples. However, if the overall system is too cold, that is, using temperatures of the lower cooling surface down to −60 °C combined with low temperatures of the upper cooling surface, control over pore orientation is lost. This is also found when viscosity of chitosan solutions is above ≈5 Pas near the freezing point. KW - unidirectional freezing KW - anisotropic porous structures KW - morphology controls KW - systematic investigations Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256330 VL - 24 IS - 3 ER - TY - JOUR A1 - Seifert, Annika A1 - Groll, Jürgen A1 - Weichhold, Jan A1 - Boehm, Anne V. A1 - Müller, Frank A. A1 - Gbureck, Uwe T1 - Phase Conversion of Ice‐Templated α‐Tricalcium Phosphate Scaffolds into Low‐Temperature Calcium Phosphates with Anisotropic Open Porosity JF - Advanced Engineering Materials N2 - The current study aims to extend the material platform for anisotropically structured calcium phosphates to low-temperature phases such as calcium-deficient hydroxyapatite (CDHA) or the secondary phosphates monetite and brushite. This is achieved by the phase conversion of highly porous α-tricalcium phosphate (α-TCP) scaffolds fabricated by ice-templating into the aforementioned phases by hydrothermal treatment or incubation in phosphoric acid. Prior to these steps, α-TCP scaffolds are either sintered for 8 h at 1400 °C or remain in their original state. Both nonsintered and sintered α-TCP specimens are converted into CDHA by hydrothermal treatment, while a transformation into monetite and brushite is achieved by incubation in phosphoric acid. Hydrothermal treatment for 72 h at 175 °C increases the porosity in nonsintered samples from 85% to 88% and from 75% to 88% in the sintered ones. An increase in the specific surface area from (1.102 ± 0.005) to (9.17 ± 0.01) m2 g−1 and from (0.190 ± 0.004) to (2.809 ± 0.002) m2 g−1 due to the phase conversion is visible for both the nonsintered and sintered samples. Compressive strength of the nonsintered samples increases significantly from (0.76 ± 0.11) to (5.29 ± 0.94) MPa due to incubation in phosphoric acid. KW - phase conversion KW - α-tricalcium phosphate Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256311 VL - 23 IS - 5 ER - TY - JOUR A1 - Schmitz, Tobias A1 - Jannasch, Maren A1 - Weigel, Tobias A1 - Moseke, Claus A1 - Gbureck, Uwe A1 - Groll, Jürgen A1 - Walles, Heike A1 - Hansmann, Jan T1 - Nanotopographical Coatings Induce an Early Phenotype-Specific Response of Primary Material-Resident M1 and M2 Macrophages JF - Materials N2 - Implants elicit an immunological response after implantation that results in the worst case in a complete implant rejection. This biomaterial-induced inflammation is modulated by macrophages and can be influenced by nanotopographical surface structures such as titania nanotubes or fractal titanium nitride (TiN) surfaces. However, their specific impact on a distinct macrophage phenotype has not been identified. By using two different levels of nanostructures and smooth samples as controls, the influence of tubular TiO2 and fractal TiN nanostructures on primary human macrophages with M1 or M2-phenotype was investigated. Therefore, nanotopographical coatings were either, directly generated by physical vapor deposition (PVD) or by electrochemical anodization of titanium PVD coatings. The cellular response of macrophages was quantitatively assessed to demonstrate a difference in biocompatibility of nanotubes in respect to human M1 and M2-macrophages. Depending on the tube diameter of the nanotubular surfaces, low cell numbers and impaired cellular activity, was detected for M2-macrophages, whereas the impact of nanotubes on M1-polarized macrophages was negligible. Importantly, we could confirm this phenotypic response on the fractal TiN surfaces. The results indicate that the investigated topographies specifically impact the macrophage M2-subtype that modulates the formation of the fibrotic capsule and the long-term response to an implant. KW - nanotopographical surfaces KW - combination of physical vapor deposition and electrochemical etching KW - defined humanized test system KW - inflammatory response Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-203378 SN - 1996-1944 VL - 13 IS - 5 ER - TY - JOUR A1 - Schmidt, Stefanie A1 - Abinzano, Florencia A1 - Mensinga, Anneloes A1 - Teßmar, Jörg A1 - Groll, Jürgen A1 - Malda, Jos A1 - Levato, Riccardo A1 - Blunk, Torsten T1 - Differential production of cartilage ECM in 3D agarose constructs by equine articular cartilage progenitor cells and mesenchymal stromal cells JF - International Journal of Molecular Sciences N2 - Identification of articular cartilage progenitor cells (ACPCs) has opened up new opportunities for cartilage repair. These cells may be used as alternatives for or in combination with mesenchymal stromal cells (MSCs) in cartilage engineering. However, their potential needs to be further investigated, since only a few studies have compared ACPCs and MSCs when cultured in hydrogels. Therefore, in this study, we compared chondrogenic differentiation of equine ACPCs and MSCs in agarose constructs as monocultures and as zonally layered co-cultures under both normoxic and hypoxic conditions. ACPCs and MSCs exhibited distinctly differential production of the cartilaginous extracellular matrix (ECM). For ACPC constructs, markedly higher glycosaminoglycan (GAG) contents were determined by histological and quantitative biochemical evaluation, both in normoxia and hypoxia. Differential GAG production was also reflected in layered co-culture constructs. For both cell types, similar staining for type II collagen was detected. However, distinctly weaker staining for undesired type I collagen was observed in the ACPC constructs. For ACPCs, only very low alkaline phosphatase (ALP) activity, a marker of terminal differentiation, was determined, in stark contrast to what was found for MSCs. This study underscores the potential of ACPCs as a promising cell source for cartilage engineering. KW - ACPC KW - chondroprogenitors KW - tissue engineering KW - MSC KW - agarose KW - hypoxia KW - ECM KW - co-culture KW - zonal KW - cartilage Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-236180 SN - 1422-0067 VL - 21 IS - 19 ER - TY - JOUR A1 - Sancho, Ana A1 - Vandersmissen, Ine A1 - Craps, Sander A1 - Luttun, Aernout A1 - Groll, Jürgen T1 - A new strategy to measure intercellular adhesion forces in mature cell-cell contacts JF - Scientific Reports N2 - Intercellular adhesion plays a major role in tissue development and homeostasis. Yet, technologies to measure mature cell-cell contacts are not available. We introduce a methodology based on fluidic probe force microscopy to assess cell-cell adhesion forces after formation of mature intercellular contacts in cell monolayers. With this method we quantify that L929 fibroblasts exhibit negligible cell-cell adhesion in monolayers whereas human endothelial cells from the umbilical artery (HUAECs) exert strong intercellular adhesion forces per cell. We use a new in vitro model based on the overexpression of Muscle Segment Homeobox 1 (MSX1) to induce Endothelial-to-Mesenchymal Transition (EndMT), a process involved in cardiovascular development and disease. We reveal how intercellular adhesion forces in monolayer decrease significantly at an early stage of EndMT and we show that cells undergo stiffening and flattening at this stage. This new biomechanical insight complements and expands the established standard biomolecular analyses. Our study thus introduces a novel tool for the assessment of mature intercellular adhesion forces in a physiological setting that will be of relevance to biological processes in developmental biology, tissue regeneration and diseases like cancer and fibrosis. KW - intercellular adhesion KW - mature cell-cell contacts KW - atomic force microscopy KW - biophysics Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170999 VL - 7 IS - 46152 ER - TY - JOUR A1 - Rödel, Michaela A1 - Teßmar, Jörg A1 - Groll, Jürgen A1 - Gbureck, Uwe T1 - Tough and Elastic alpha-Tricalcium Phosphate Cement Composites with Degradable PEG-Based Cross-Linker JF - Materials N2 - Dual setting cements composed of an in situ forming hydrogel and a reactive mineral phase combine high compressive strength of the cement with sufficient ductility and bending strength of the polymeric network. Previous studies were focused on the modification with non-degradable hydrogels based on 2-hydroxyethyl methacrylate (HEMA). Here, we describe the synthesis of suitable triblock degradable poly(ethylene glycol)-poly(lactide) (PEG-PLLA) cross-linker to improve the resorption capacity of such composites. A study with four different formulations was established. As reference, pure hydroxyapatite (HA) cements and composites with 40 wt% HEMA in the liquid cement phase were produced. Furthermore, HEMA was modified with 10 wt% of PEG-PLLA cross-linker or a test series containing only 25% cross-linker was chosen for composites with a fully degradable polymeric phase. Hence, we developed suitable systems with increased elasticity and 5-6 times higher toughn ess values in comparison to pure inorganic cement matrix. Furthermore, conversion rate from alpha-tricalcium phosphate (alpha-TCP) to HA was still about 90% for all composite formulations, whereas crystal size decreased. Based on this material development and advancement for a dual setting system, we managed to overcome the drawback of brittleness for pure calcium phosphate cements. KW - dual setting system KW - bending strength KW - calcium phosphate cement KW - composite material KW - HEMA KW - hydroxyapatite KW - free radical polymerization Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226437 VL - 12 IS - 53 ER - TY - JOUR A1 - Rödel, Michaela A1 - Baumann, Katrin A1 - Groll, Jürgen A1 - Gbureck, Uwe T1 - Simultaneous structuring and mineralization of silk fibroin scaffolds JF - Journal of Tissue Engineering N2 - Silk fibroin is commonly used as scaffold material for tissue engineering applications. In combination with a mineralization with different calcium phosphate phases, it can also be applied as material for bone regeneration. Here, we present a study which was performed to produce mineralized silk fibroin scaffolds with controlled macroporosity. In contrast to former studies, our approach focused on a simultaneous gelation and mineralization of silk fibroin by immersion of frozen silk fibroin monoliths in acidic calcium phosphate solutions. This was achieved by thawing frozen silk fibroin monoliths in acidic calcium phosphate solution, leading to the precipitation of monocalcium phosphate within the silk fibroin matrix. In the second approach, a conversion of incorporated -tricalcium phosphate particles into brushite was successfully achieved. Furthermore, a controlled cryostructuring process of silk fibroin scaffolds was carried out leading to the formation of parallel-oriented pores with diameters of 30-50 mu m. KW - Brushite KW - calcium phosphate KW - cryostructuring KW - hydrogel KW - mineralization KW - silk fibroin scaffolds Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226427 VL - 9 ER - TY - JOUR A1 - Ryma, Matthias A1 - Tylek, Tina A1 - Liebscher, Julia A1 - Blum, Carina A1 - Fernandez, Robin A1 - Böhm, Christoph A1 - Kastenmüller, Wolfgang A1 - Gasteiger, Georg A1 - Groll, Jürgen T1 - Translation of collagen ultrastructure to biomaterial fabrication for material-independent but highly efficient topographic immunomodulation JF - Advanced materials N2 - Supplement-free induction of cellular differentiation and polarization solely through the topography of materials is an auspicious strategy but has so far significantly lagged behind the efficiency and intensity of media-supplementation-based protocols. Consistent with the idea that 3D structural motifs in the extracellular matrix possess immunomodulatory capacity as part of the natural healing process, it is found in this study that human-monocyte-derived macrophages show a strong M2a-like prohealing polarization when cultured on type I rat-tail collagen fibers but not on collagen I films. Therefore, it is hypothesized that highly aligned nanofibrils also of synthetic polymers, if packed into larger bundles in 3D topographical biomimetic similarity to native collagen I, would induce a localized macrophage polarization. For the automated fabrication of such bundles in a 3D printing manner, the strategy of “melt electrofibrillation” is pioneered by the integration of flow-directed polymer phase separation into melt electrowriting and subsequent selective dissolution of the matrix polymer postprocessing. This process yields nanofiber bundles with a remarkable structural similarity to native collagen I fibers, particularly for medical-grade poly(ε-caprolactone). These biomimetic fibrillar structures indeed induce a pronounced elongation of human-monocyte-derived macrophages and unprecedentedly trigger their M2-like polarization similar in efficacy as interleukin-4 treatment. KW - biofabrication KW - extracellular matrix KW - immunomodulation KW - macrophages KW - melt electrofibrillation KW - melt electrowriting Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256381 VL - 33 IS - 33 ER - TY - JOUR A1 - Ryma, Matthias A1 - Genç, Hatice A1 - Nadernezhad, Ali A1 - Paulus, Ilona A1 - Schneidereit, Dominik A1 - Friedrich, Oliver A1 - Andelovic, Kristina A1 - Lyer, Stefan A1 - Alexiou, Christoph A1 - Cicha, Iwona A1 - Groll, Jürgen T1 - A Print-and-Fuse Strategy for Sacrificial Filaments Enables Biomimetically Structured Perfusable Microvascular Networks with Functional Endothelium Inside 3D Hydrogels JF - Advanced Materials N2 - 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. KW - hydrogels KW - microvasculature KW - melt electrowriting Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318532 VL - 34 IS - 28 ER - TY - JOUR A1 - Projahn, Delia A1 - Simsekyilmaz, Sakine A1 - Singh, Smriti A1 - Kanzler, Isabella A1 - Kramp, Birgit K. A1 - Langer, Marcella A1 - Burlacu, Alexandrina A1 - Bernhagen, Jürgen A1 - Klee, Doris A1 - Zernecke, Alma A1 - Hackeng, Tilman M. A1 - Groll, Jürgen A1 - Weber, Christian A1 - Liehn, Elisa A. A1 - Koenen, Roy R. T1 - Controlled intramyocardial release of engineered chemokines by biodegradable hydrogels as a treatment approach of myocardial infarction JF - Journal of Cellular and Molecular Medicine N2 - Myocardial infarction (MI) induces a complex inflammatory immune response, followed by the remodelling of the heart muscle and scar formation. The rapid regeneration of the blood vessel network system by the attraction of hematopoietic stem cells is beneficial for heart function. Despite the important role of chemokines in these processes, their use in clinical practice has so far been limited by their limited availability over a long time-span in vivo. Here, a method is presented to increase physiological availability of chemokines at the site of injury over a defined time-span and simultaneously control their release using biodegradable hydrogels. Two different biodegradable hydrogels were implemented, a fast degradable hydrogel (FDH) for delivering Met-CCL5 over 24hrs and a slow degradable hydrogel (SDH) for a gradual release of protease-resistant CXCL12 (S4V) over 4weeks. We demonstrate that the time-controlled release using Met-CCL5-FDH and CXCL12 (S4V)-SDH suppressed initial neutrophil infiltration, promoted neovascularization and reduced apoptosis in the infarcted myocardium. Thus, we were able to significantly preserve the cardiac function after MI. This study demonstrates that time-controlled, biopolymer-mediated delivery of chemokines represents a novel and feasible strategy to support the endogenous reparatory mechanisms after MI and may compliment cell-based therapies. KW - chemokines KW - therapy KW - cardiovascular pharmacology KW - remodelling KW - endothelial progenitor cells KW - left-ventricular function KW - heart-failure KW - rat model KW - recruitment KW - factor-I Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-116597 SN - 1582-4934 VL - 18 IS - 5 ER - TY - JOUR A1 - Pinzner, Florian A1 - Keller, Thorsten A1 - Mut, Jürgen A1 - Bechold, Julian A1 - Seibel, Jürgen A1 - Groll, Jürgen T1 - Polyoxazolines with a vicinally double-bioactivated terminus for biomacromolecular affinity assessment JF - Sensors N2 - Interactions between proteins and carbohydrates with larger biomacromolecules, e.g., lectins, are usually examined using self-assembled monolayers on target gold surfaces as a simplified model measuring setup. However, most of those measuring setups are either limited to a single substrate or do not allow for control over ligand distance and spacing. Here, we develop a synthetic strategy, consisting of a cascade of a thioesterification, native chemical ligation (NCL) and thiol-ene reaction, in order to create three-component polymer conjugates with a defined double bioactivation at the chain end. The target architecture is the vicinal attachment of two biomolecule residues to the α telechelic end point of a polymer and a thioether group at the ω chain end for fixating the conjugate to a gold sensor chip surface. As proof-of-principle studies for affinity measurements, we demonstrate the interaction between covalently bound mannose and ConA in surface acoustic wave (SAW) and surface plasmon resonance (SPR) experiments. KW - polyoxazolines KW - functionalization KW - lectin Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239530 SN - 1424-8220 VL - 21 IS - 9 ER - TY - JOUR A1 - Pereira, Ana Rita A1 - Trivanović, Drenka A1 - Stahlhut, Philipp A1 - Rudert, Maximilian A1 - Groll, Jürgen A1 - Herrmann, Marietta T1 - Preservation of the naïve features of mesenchymal stromal cells in vitro: Comparison of cell- and bone-derived decellularized extracellular matrix JF - Journal of Tissue Engineering N2 - 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 naïve 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 naïve features of BM-MSC. KW - decellularization KW - bone model KW - stem cell niche KW - stemness KW - osteogenesis KW - 3D models Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-268835 VL - 13 ER -