@article{BrendtkeWiehlGroeberetal.2016,
  author    = {Brendtke, Rico and Wiehl, Michael and Groeber, Florian and Schwarz, Thomas and Walles, Heike and Hansmann, Jan},
  title     = {Feasibility Study on a Microwave-Based Sensor for Measuring Hydration Level Using Human Skin Models},
  series = {PLoS ONE},
  volume    = {11},
  journal   = {PLoS ONE},
  number    = {4},
  doi       = {10.1371/journal.pone.0153145},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-179934},
  year      = {2016},
  abstract  = {Tissue dehydration results in three major types of exsiccosis—hyper-, hypo-, or isonatraemia. All three types entail alterations of salt concentrations leading to impaired biochemical processes, and can finally cause severe morbidity. The aim of our study was to demonstrate the feasibility of a microwave-based sensor technology for the non-invasive measurement of the hydration status. Electromagnetic waves at high frequencies interact with molecules, especially water. Hence, if a sample contains free water molecules, this can be detected in a reflected microwave signal. To develop the sensor system, human three-dimensional skin equivalents were instituted as a standardized test platform mimicking reproducible exsiccosis scenarios. Therefore, skin equivalents with a specific hydration and density of matrix components were generated and microwave measurements were performed. Hydration-specific spectra allowed deriving the hydration state of the skin models. A further advantage of the skin equivalents was the characterization of the impact of distinct skin components on the measured signals to investigate mechanisms of signal generation. The results demonstrate the feasibility of a non-invasive microwave-based hydration sensor technology. The sensor bears potential to be integrated in a wearable medical device for personal health monitoring.},
  language  = {en}
}
@article{MollReboredoSchwarzetal.2013,
  author    = {Moll, Corinna and Reboredo, Jenny and Schwarz, Thomas and Appelt, Antje and Sch{\"u}rlein, Sebastian and Walles, Heike and Nietzer, Sarah},
  title     = {Tissue Engineering of a Human 3D in vitro Tumor Test System},
  series = {Journal of Visualized Experiments},
  volume    = {78},
  journal   = {Journal of Visualized Experiments},
  number    = {e50460},
  doi       = {10.3791/50460},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132277},
  year      = {2013},
  abstract  = {Cancer is one of the leading causes of death worldwide. Current therapeutic strategies are predominantly developed in 2D culture systems, which inadequately reflect physiological conditions in vivo. Biological 3D matrices provide cells an environment in which cells can self-organize, allowing the study of tissue organization and cell differentiation. Such scaffolds can be seeded with a mixture of different cell types to study direct 3D cell-cell-interactions. To mimic the 3D complexity of cancer tumors, our group has developed a 3D in vitro tumor test system. Our 3D tissue test system models the in vivo situation of malignant peripheral nerve sheath tumors (MPNSTs), which we established with our decellularized porcine jejunal segment derived biological vascularized scaffold (BioVaSc). In our model, we reseeded a modified BioVaSc matrix with primary fibroblasts, microvascular endothelial cells (mvECs) and the S462 tumor cell line For static culture, the vascular structure of the BioVaSc is removed and the remaining scaffold is cut open on one side (Small Intestinal Submucosa SIS-Muc). The resulting matrix is then fixed between two metal rings (cell crowns). Another option is to culture the cell-seeded SIS-Muc in a flow bioreactor system that exposes the cells to shear stress. Here, the bioreactor is connected to a peristaltic pump in a self-constructed incubator. A computer regulates the arterial oxygen and nutrient supply via parameters such as blood pressure, temperature, and flow rate. This setup allows for a dynamic culture with either pressure-regulated pulsatile or constant flow. In this study, we could successfully establish both a static and dynamic 3D culture system for MPNSTs. The ability to model cancer tumors in a more natural 3D environment will enable the discovery, testing, and validation of future pharmaceuticals in a human-like model.},
  language  = {en}
}
@article{SchwedhelmZdziebloAppeltMenzeletal.2019,
  author    = {Schwedhelm, Ivo and Zdzieblo, Daniela and Appelt-Menzel, Antje and Berger, Constantin and Schmitz, Tobias and Schuldt, Bernhard and Franke, Andre and M{\"u}ller, Franz-Josef and Pless, Ole and Schwarz, Thomas and Wiedemann, Philipp and Walles, Heike and Hansmann, Jan},
  title     = {Automated real-time monitoring of human pluripotent stem cell aggregation in stirred tank reactors},
  series = {Scientific Reports},
  volume    = {9},
  journal   = {Scientific Reports},
  doi       = {10.1038/s41598-019-48814-w},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-202649},
  pages     = {12297},
  year      = {2019},
  abstract  = {The culture of human induced pluripotent stem cells (hiPSCs) at large scale becomes feasible with the aid of scalable suspension setups in continuously stirred tank reactors (CSTRs). Innovative monitoring options and emerging automated process control strategies allow for the necessary highly defined culture conditions. Next to standard process characteristics such as oxygen consumption, pH, and metabolite turnover, a reproducible and steady formation of hiPSC aggregates is vital for process scalability. In this regard, we developed a hiPSC-specific suspension culture unit consisting of a fully monitored CSTR system integrated into a custom-designed and fully automated incubator. As a step towards cost-effective hiPSC suspension culture and to pave the way for flexibility at a large scale, we constructed and utilized tailored miniature CSTRs that are largely made from three-dimensional (3D) printed polylactic acid (PLA) filament, which is a low-cost material used in fused deposition modelling. Further, the monitoring tool for hiPSC suspension cultures utilizes in situ microscopic imaging to visualize hiPSC aggregation in real-time to a statistically significant degree while omitting the need for time-intensive sampling. Suitability of our culture unit, especially concerning the developed hiPSC-specific CSTR system, was proven by demonstrating pluripotency of CSTR-cultured hiPSCs at RNA (including PluriTest) and protein level.},
  language  = {en}
}
@article{SchmidTarauRossietal.2018,
  author    = {Schmid, Richard and Tarau, Ioana-Sandra and Rossi, Angela and Leonhardt, Stefan and Schwarz, Thomas and Schuerlein, Sebastian and Lotz, Christian and Hansmann, Jan},
  title     = {In Vivo-Like Culture Conditions in a Bioreactor Facilitate Improved Tissue Quality in Corneal Storage},
  series = {Biotechnology Journal},
  volume    = {13},
  journal   = {Biotechnology Journal},
  number    = {1,1700344},
  doi       = {10.1002/biot.201700344},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228620},
  pages     = {1-7},
  year      = {2018},
  abstract  = {The cornea is the most-transplanted tissue worldwide. However, the availability and quality of grafts are limited due to the current methods of corneal storage. In this study, a dynamic bioreactor system is employed to enable the control of intraocular pressure and the culture at the air-liquid interface. Thereby, in vivo-like storage conditions are achieved. Different media combinations for endothelium and epithelium are tested in standard and dynamic conditions to enhance the viability of the tissue. In contrast to culture conditions used in eye banks, the combination of the bioreactor and biochrom medium 1 allows to preserve the corneal endothelium and the epithelium. Assessment of transparency, swelling, and the trans-epithelial-electrical-resistance (TEER) strengthens the impact of the in vivo-like tissue culture. For example, compared to corneas stored under static conditions, significantly lower optical densities and significantly higher TEER values were measured (p-value <0.05). Furthermore, healing of epithelial defects is enabled in the bioreactor, characterized by re-epithelialization and initiated stromal regeneration. Based on the obtained results, an easy-to-use 3D-printed bioreactor composed of only two parts was derived to translate the technology from the laboratory to the eye banks. This optimized bioreactor facilitates noninvasive microscopic monitoring. The improved storage conditions ameliorate the quality of corneal grafts and the storage time in the eye banks to increase availability and reduce re-grafting.},
  language  = {en}
}
@article{NietzerBaurSieberetal.2016,
  author    = {Nietzer, Sarah and Baur, Florentin and Sieber, Stefan and Hansmann, Jan and Schwarz, Thomas and Stoffer, Carolin and H{\"a}fner, Heide and Gasser, Martin and Waaga-Gasser, Ana Maria and Walles, Heike and Dandekar, Gudrun},
  title     = {Mimicking metastases including tumor stroma: a new technique to generate a three-dimensional colorectal cancer model based on a biological decellularized intestinal scaffold},
  series = {Tissue Engineering Part C-Methods},
  volume    = {22},
  journal   = {Tissue Engineering Part C-Methods},
  number    = {7},
  doi       = {10.1089/ten.tec.2015.0557},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-188202},
  pages     = {621-635},
  year      = {2016},
  abstract  = {Tumor models based on cancer cell lines cultured two-dimensionally (2D) on plastic lack histological complexity and functionality compared to the native microenvironment. Xenogenic mouse tumor models display higher complexity but often do not predict human drug responses accurately due to species-specific differences. We present here a three-dimensional (3D) in vitro colon cancer model based on a biological scaffold derived from decellularized porcine jejunum (small intestine submucosa+mucosa, SISmuc). Two different cell lines were used in monoculture or in coculture with primary fibroblasts. After 14 days of culture, we demonstrated a close contact of human Caco2 colon cancer cells with the preserved basement membrane on an ultrastructural level as well as morphological characteristics of a well-differentiated epithelium. To generate a tissue-engineered tumor model, we chose human SW480 colon cancer cells, a reportedly malignant cell line. Malignant characteristics were confirmed in 2D cell culture: SW480 cells showed higher vimentin and lower E-cadherin expression than Caco2 cells. In contrast to Caco2, SW480 cells displayed cancerous characteristics such as delocalized E-cadherin and nuclear location of beta-catenin in a subset of cells. One central drawback of 2D cultures-especially in consideration of drug testing-is their artificially high proliferation. In our 3D tissue-engineered tumor model, both cell lines showed decreased numbers of proliferating cells, thus correlating more precisely with observations of primary colon cancer in all stages (UICC I-IV). Moreover, vimentin decreased in SW480 colon cancer cells, indicating a mesenchymal to epithelial transition process, attributed to metastasis formation. Only SW480 cells cocultured with fibroblasts induced the formation of tumor-like aggregates surrounded by fibroblasts, whereas in Caco2 cocultures, a separate Caco2 cell layer was formed separated from the fibroblast compartment beneath. To foster tissue generation, a bioreactor was constructed for dynamic culture approaches. This induced a close tissue-like association of cultured tumor cells with fibroblasts reflecting tumor biopsies. Therapy with 5-fluorouracil (5-FU) was effective only in 3D coculture. In conclusion, our 3D tumor model reflects human tissue-related tumor characteristics, including lower tumor cell proliferation. It is now available for drug testing in metastatic context-especially for substances targeting tumor-stroma interactions.},
  language  = {en}
}
@article{HaeusnerHerbstBittorfetal.2021,
  author    = {Haeusner, Sebastian and Herbst, Laura and Bittorf, Patrick and Schwarz, Thomas and Henze, Chris and Mauermann, Marc and Ochs, Jelena and Schmitt, Robert and Blache, Ulrich and Wixmerten, Anke and Miot, Sylvie and Martin, Ivan and Pullig, Oliver},
  title     = {From Single Batch to Mass Production-Automated Platform Design Concept for a Phase II Clinical Trial Tissue Engineered Cartilage Product},
  series = {Frontiers in Medicine},
  volume    = {8},
  journal   = {Frontiers in Medicine},
  issn      = {2296-858X},
  doi       = {10.3389/fmed.2021.712917},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-244631},
  year      = {2021},
  abstract  = {Advanced Therapy Medicinal Products (ATMP) provide promising treatment options particularly for unmet clinical needs, such as progressive and chronic diseases where currently no satisfying treatment exists. Especially from the ATMP subclass of Tissue Engineered Products (TEPs), only a few have yet been translated from an academic setting to clinic and beyond. A reason for low numbers of TEPs in current clinical trials and one main key hurdle for TEPs is the cost and labor-intensive manufacturing process. Manual production steps require experienced personnel, are challenging to standardize and to scale up. Automated manufacturing has the potential to overcome these challenges, toward an increasing cost-effectiveness. One major obstacle for automation is the control and risk prevention of cross contaminations, especially when handling parallel production lines of different patient material. These critical steps necessitate validated effective and efficient cleaning procedures in an automated system. In this perspective, possible technologies, concepts and solutions to existing ATMP manufacturing hurdles are discussed on the example of a late clinical phase II trial TEP. In compliance to Good Manufacturing Practice (GMP) guidelines, we propose a dual arm robot based isolator approach. Our novel concept enables complete process automation for adherent cell culture, and the translation of all manual process steps with standard laboratory equipment. Moreover, we discuss novel solutions for automated cleaning, without the need for human intervention. Consequently, our automation concept offers the unique chance to scale up production while becoming more cost-effective, which will ultimately increase TEP availability to a broader number of patients.},
  language  = {en}
}
@article{HeydarianSchweinlinSchwarzetal.2021,
  author    = {Heydarian, Motaharehsadat and Schweinlin, Matthias and Schwarz, Thomas and Rawal, Ravisha and Walles, Heike and Metzger, Marco and Rudel, Thomas and Kozjak-Pavlovic, Vera},
  title     = {Triple co-culture and perfusion bioreactor for studying the interaction between Neisseria gonorrhoeae and neutrophils: A novel 3D tissue model for bacterial infection and immunity},
  series = {Journal of Tissue Engineering},
  volume    = {12},
  journal   = {Journal of Tissue Engineering},
  doi       = {10.1177/2041731420988802},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-259032},
  pages     = {2041731420988802},
  year      = {2021},
  abstract  = {Gonorrhea, a sexually transmitted disease caused by the bacteria Neisseria gonorrhoeae, is characterized by a large number of neutrophils recruited to the site of infection. Therefore, proper modeling of the N. gonorrhoeae interaction with neutrophils is very important for investigating and understanding the mechanisms that gonococci use to evade the immune response. We have used a combination of a unique human 3D tissue model together with a dynamic culture system to study neutrophil transmigration to the site of N. gonorrhoeae infection. The triple co-culture model consisted of epithelial cells (T84 human colorectal carcinoma cells), human primary dermal fibroblasts, and human umbilical vein endothelial cells on a biological scaffold (SIS). After the infection of the tissue model with N. gonorrhoeae, we introduced primary human neutrophils to the endothelial side of the model using a perfusion-based bioreactor system. By this approach, we were able to demonstrate the activation and transmigration of neutrophils across the 3D tissue model and their recruitment to the site of infection. In summary, the triple co-culture model supplemented by neutrophils represents a promising tool for investigating N. gonorrhoeae and other bacterial infections and interactions with the innate immunity cells under conditions closely resembling the native tissue environment.},
  language  = {en}
}