Fraunhofer Institute for Interfacial Engineering and Biotechnology

Stuttgart, Germany

Fraunhofer Institute for Interfacial Engineering and Biotechnology

Stuttgart, Germany
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Oehr C.,Fraunhofer Institute for Interfacial Engineering and Biotechnology
Vakuum in Forschung und Praxis | Year: 2017

Cost Structure of Plasma Processes — The share of investment costs and operating expense in vacuum coating processes. At a first glance coating costs of plasma processes seem to be dominated by high investments. Here it is shown that operating costs are at least of the same importance. Thus, it is reasonable to accept coating costs as only one contribution amongst others to the overall production costs. The example „solar cells”︁ shows that further enhancement of the coating process is less effective compared to an increase of energy conversion efficiency. On the other hand it appears more effective for cost reduction of hard coatings to decrease energy consumption and to increase the deposition rate instead of minimization of investment costs for the coating machine. The cost structures of depositions from the liquid phase and plasma processes are of the same order but growing environmental demands clearly favor the latter one (no liquid waste, etc.). The commonly used argument, that it is always preferable to run coating processes at atmospheric pressure without the use of (expensive) vacuum equipment rather than under vacuum conditions needs to be reconsidered particularly when noble gases are necessary at atmospheric pressure to obtain equal qualities of the coatings. Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


Hinderer S.,University of Tübingen | Hinderer S.,Fraunhofer Institute for Interfacial Engineering and Biotechnology | Layland S.L.,University of Tübingen | Layland S.L.,Fraunhofer Institute for Interfacial Engineering and Biotechnology | And 3 more authors.
Advanced Drug Delivery Reviews | Year: 2016

Regenerative strategies such as stem cell-based therapies and tissue engineering applications are being developed with the aim to replace, remodel, regenerate or support damaged tissues and organs. In addition to careful cell type selection, the design of appropriate three-dimensional (3D) scaffolds is essential for the generation of bio-inspired replacement tissues. Such scaffolds are usually made of degradable or non-degradable biomaterials and can serve as cell or drug carriers. The development of more effective and efficient drug carrier systems is also highly relevant for novel cancer treatment strategies. In this review, we provide a summary of current approaches that employ ECM and ECM-like materials, or ECM-synthetic polymer hybrids, as biomaterials in the field of regenerative medicine. We further discuss the utilization of such materials for cell and drug delivery, and highlight strategies for their use as vehicles for cancer therapy. © 2015 The Authors.


Walles T.,Robert Bosch GmbH | Walles T.,Fraunhofer Institute for Interfacial Engineering and Biotechnology
Advanced Drug Delivery Reviews | Year: 2011

The development of substitutes for the human trachea or its bronchial tree represents a niche application in the rapidly advancing scientific field of Regenerative Medicine. Despite a comparatively small research foundation in the field of tracheo-bronchial bioengineering, four different approaches have already been translated into clinical settings and applied in patients. This can be attributed to the lack of established treatment options for a small group of patients with extensive major airway disease. In this review, the clinical background and tissue-specific basics of tracheo-bronchial bioengineering will be evaluated. Focusing on the clinical applications of bioengineered tracheal tissues, a "top-down" or "bedside-to-bench" analysis is performed in order to guide future basic and clinical research activities for airway bioengineering. © 2011 Elsevier B.V.


Novosel E.C.,University of Stuttgart | Kleinhans C.,University of Stuttgart | Kluger P.J.,University of Stuttgart | Kluger P.J.,Fraunhofer Institute for Interfacial Engineering and Biotechnology
Advanced Drug Delivery Reviews | Year: 2011

The main limitation in engineering in vitro tissues is the lack of a sufficient blood vessel system - the vascularization. In vivo almost all tissues are supplied by these endothelial cell coated tubular networks. Current strategies to create vascularized tissues are discussed in this review. The first strategy is based on the endothelial cells and their ability to form new vessels known as neoangiogenesis. Herein prevascularization techniques are compared to approaches in which biomolecules, such as growth factors, cytokines, peptides and proteins as well as cells are applied to generate new vessels. The second strategy is focused on scaffold-based techniques. Naturally-derived scaffolds, which contain vessels, are distinguished from synthetically manufactured matrices. Advantages and pitfalls of the approaches to create vascularized tissues in vitro are outlined and feasible future strategies are discussed. © 2010 Elsevier B.V.


Brauchle E.,Fraunhofer Institute for Interfacial Engineering and Biotechnology | Brauchle E.,University of Stuttgart | Thude S.,Fraunhofer Institute for Interfacial Engineering and Biotechnology | Brucker S.Y.,University of Tübingen | And 3 more authors.
Scientific Reports | Year: 2014

Although apoptosis and necrosis have distinct features, the identification and discrimination of apoptotic and necrotic cell death in vitro is challenging. Immunocytological and biochemical assays represent the current gold standard for monitoring cell death pathways; however, these standard assays are invasive, render large numbers of cells and impede continuous monitoring experiments. In this study, both room temperature (RT)-induced apoptosis and heat-triggered necrosis were analyzed in individual Saos-2 and SW-1353 cells by utilizing Raman microspectroscopy. A targeted analysis of defined cell death modalities, including early and late apoptosis as well as necrosis, was facilitated based on the combination of Raman spectroscopy with fluorescence microscopy. Spectral shifts were identified in the two cell lines that reflect biochemical changes specific for either RT-induced apoptosis or heat-mediated necrosis. A supervised classification model specified apoptotic and necrotic cell death based on single cell Raman spectra. To conclude, Raman spectroscopy allows a non-invasive, continuous monitoring of cell death, which may help shedding new light on complex pathophysiological or drug-induced cell death processes. © 2014 Macmillan Publishers Limited.


Surmenev R.A.,Fraunhofer Institute for Interfacial Engineering and Biotechnology | Surmeneva M.A.,Tomsk Polytechnic University | Ivanova A.A.,Tomsk Polytechnic University
Acta Biomaterialia | Year: 2014

A systematic analysis of results available from in vitro, in vivo and clinical trials on the effects of biocompatible calcium phosphate (CaP) coatings is presented. An overview of the most frequently used methods to prepare CaP-based coatings was conducted. Dense, homogeneous, highly adherent and biocompatible CaP or hybrid organic/inorganic CaP coatings with tailored properties can be deposited. It has been demonstrated that CaP coatings have a significant effect on the bone regeneration process. In vitro experiments using different cells (e.g. SaOS-2, human mesenchymal stem cells and osteoblast-like cells) have revealed that CaP coatings enhance cellular adhesion, proliferation and differentiation to promote bone regeneration. However, in vivo, the exact mechanism of osteogenesis in response to CaP coatings is unclear; indeed, there are conflicting reports of the effectiveness of CaP coatings, with results ranging from highly effective to no significant or even negative effects. This review therefore highlights progress in CaP coatings for orthopaedic implants and discusses the future research and use of these devices. Currently, an exciting area of research is in bioactive hybrid composite CaP-based coatings containing both inorganic (CaP coating) and organic (collagen, bone morphogenetic proteins, arginylglycylaspartic acid etc.) components with the aim of promoting tissue ingrowth and vascularization. Further investigations are necessary to reveal the relative influences of implant design, surgical procedure, and coating characteristics (thickness, structure, topography, porosity, wettability etc.) on the long-term clinical effects of hybrid CaP coatings. In addition to commercially available plasma spraying, other effective routes for the fabrication of hybrid CaP coatings for clinical use still need to be determined and current progress is discussed. © 2013 Acta Materialia Inc.


Lemuth K.,Fraunhofer Institute for Interfacial Engineering and Biotechnology | Steuer K.,University of Stuttgart | Albermann C.,University of Stuttgart
Microbial Cell Factories | Year: 2011

Background: The xanthophyll astaxanthin is a high-value compound with applications in the nutraceutical, cosmetic, food, and animal feed industries. Besides chemical synthesis and extraction from naturally producing organisms like Haematococcus pluvialis, heterologous biosynthesis in non-carotenogenic microorganisms like Escherichia coli, is a promising alternative for sustainable production of natural astaxanthin. Recent achievements in the metabolic engineering of E. coli strains have led to a significant increase in the productivity of carotenoids like lycopene or β-carotene by increasing the metabolic flux towards the isoprenoid precursors. For the heterologous biosynthesis of astaxanthin in E. coli, however, the conversion of β-carotene to astaxanthin is obviously the most critical step towards an efficient biosynthesis of astaxanthin.Results: Here we report the construction of the first plasmid-free E. coli strain that produces astaxanthin as the sole carotenoid compound with a yield of 1.4 mg/g cdw (E. coli BW-ASTA). This engineered E. coli strain harbors xanthophyll biosynthetic genes from Pantoea ananatis and Nostoc punctiforme as individual expression cassettes on the chromosome and is based on a β-carotene-producing strain (E. coli BW-CARO) recently developed in our lab. E. coli BW-CARO has an enhanced biosynthesis of the isoprenoid precursor isopentenyl diphosphate (IPP) and produces β-carotene in a concentration of 6.2 mg/g cdw. The expression of crtEBIY along with the β-carotene-ketolase gene crtW148 (NpF4798) and the β-carotene-hydroxylase gene (crtZ) under controlled expression conditions in E. coli BW-ASTA directed the pathway exclusively towards the desired product astaxanthin (1.4 mg/g cdw).Conclusions: By using the λ-Red recombineering technique, genes encoding for the astaxanthin biosynthesis pathway were stably integrated into the chromosome of E. coli. The expression levels of chromosomal integrated recombinant biosynthetic genes were varied and adjusted to improve the ratios of carotenoids produced by this E. coli strain. The strategy presented, which combines chromosomal integration of biosynthetic genes with the possibility of adjusting expression by using different promoters, might be useful as a general approach for the construction of stable heterologous production strains synthesizing natural products. This is the case especially for heterologous pathways where excessive protein overexpression is a hindrance. © 2011 Lemuth et al; licensee BioMed Central Ltd.


Hoch E.,University of Stuttgart | Tovar G.E.,Fraunhofer Institute for Interfacial Engineering and Biotechnology | Borchers K.,Fraunhofer Institute for Interfacial Engineering and Biotechnology
European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery | Year: 2014

Free-form fabrication techniques, often referred to as '3D printing', are currently tested with regard to the processing of biological and biocompatible materials in general and for fabrication of vessel-like structures in particular. Such computer-controlled methods assemble 3D objects by layer-wise deposition or layer-wise cross-linking of materials. They use, for example, nozzle-based deposition of hydrogels and cells, drop-on-demand inkjet-printing of cell suspensions with subsequent cross-linking, layer-by-layer cross-linking of synthetic or biological polymers by selective irradiation with light and even laser-induced deposition of single cells. The need of vessel-like structures has become increasingly crucial for the supply of encapsulated cells for 3D tissue engineering, or even with regard to future application such as vascular grafts. The anticipated potential of providing tubes with tailored branching geometries made of biocompatible or biological materials pushes future visions of patient-specific vascularized tissue substitutions, tissue-engineered blood vessels and bio-based vascular grafts. We review here the early attempts of bringing together innovative free-form manufacturing processes with bio-based and biodegradable materials. The presented studies provide many important proofs of concepts such as the possibility to integrate viable cells into computer-controlled processes and the feasibility of supplying cells in a hydrogel matrix by generation of a network of perfused channels. Several impressive results in the generation of complex shapes and high-aspect-ratio tubular structures demonstrate the potential of additive assembly methods. Yet, it also becomes obvious that there remain major challenges to simultaneously match all material requirements in terms of biological functions (cell function supporting properties), physicochemical functions (mechanical properties of the printed material) and process-related (viscosity, cross-linkability) functions, towards the demanding goal of biofabricating artificial blood vessels. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.


Muller M.,Fraunhofer Institute for Interfacial Engineering and Biotechnology | Oehr C.,Fraunhofer Institute for Interfacial Engineering and Biotechnology
Plasma Processes and Polymers | Year: 2011

The potential of contact angle measurements (CAM) as an analytical tool to characterize surface treatments or modifications is often not fully exploited. Agreeing with Strobel and Lyons, comparing contact angles is often much more reasonable than comparing deduced data like surface energies, because the latter are based on models, in turn involving the influence and knowledge of intermolecular forces at the respective interfaces. For a comprehensive picture, the measurement of contact angles itself has to be considered together with the appropriate model and the available techniques to carry out CAM. An appropriate measurement procedure will be given and a brief discussion of some models to derive free surface energy from CAM. The information that could be derived from contact angle measurements is very useful to characterize the outermost layer of a surface until it is carried out carefully. To compare the results with other working groups it is essential to describe the measurement procedure properly. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Rupp S.,Fraunhofer Institute for Interfacial Engineering and Biotechnology
Engineering in Life Sciences | Year: 2013

Within the last decade, biotechnology gained pace in substituting petro-based products for the chemical industries. This is visible with the appearance of bio-based products in the market, from biosurfactants to bio-based polymers like polylactic acid to bio-ethylene. These technologies are mainly based on established fermentation technologies fostered by the use of renewable resources, culminating in the establishment of biorefineries that may be connected directly to the existing chemical infrastructure. Besides these large-scale technologies, the combination of molecular technologies, microfluidic devices, and enzymatic and cell-free conversions are currently developed to create new bioproduction systems enabling the production of compounds that may not be produced within a cell. This article summarizes some of the current ideas that are currently in development paving the way for a next generation of biotechnology. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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