@article{HaaseKrostSauteretal.2017, author = {Haase, Tobias and Krost, Annalena and Sauter, Tilman and Kratz, Karl and Peter, Jan and Kamann, Stefanie and Jung, Friedrich and Lendlein, Andreas and Zohlnh{\"o}fer, Dietlind and R{\"u}der, Constantin}, title = {In vivo biocompatibility assessment of poly (ether imide) electrospun scaffolds}, series = {Journal of Tissue Engineering and Regenerative Medicine}, volume = {11}, journal = {Journal of Tissue Engineering and Regenerative Medicine}, number = {4}, publisher = {Wiley}, address = {Hoboken}, issn = {1932-6254}, doi = {10.1002/term.2002}, pages = {1034 -- 1044}, year = {2017}, abstract = {Poly(ether imide) (PEI), which can be chemically functionalized with biologically active ligands, has emerged as a potential biomaterial for medical implants. Electrospun PEI scaffolds have shown advantageous properties, such as enhanced endothelial cell adherence, proliferation and low platelet adhesion in in vitro experiments. In this study, the in vivo behaviour of electrospun PEI scaffolds and PEI films was examined in a murine subcutaneous implantation model. Electrospun PEI scaffolds and films were surgically implanted subcutaneously in the dorsae of mice. The surrounding subcutaneous tissue response was examined via histopathological examination at 7 and 28days after implantation. No serious adverse events were observed for both types of PEI implants. The presence of macrophages or foreign body giant cells in the vicinity of the implants and the formation of a fibrous capsule indicated a normal foreign body reaction towards PEI films and scaffolds. Capsule thickness and inflammatory infiltration cells significantly decreased for PEI scaffolds during days 7-28 while remaining unchanged for PEI films. The infiltration of cells into the implant was observed for PEI scaffolds 7days after implantation and remained stable until 28days of implantation. Additionally some, but not all, PEI scaffold implants induced the formation of functional blood vessels in the vicinity of the implants. Conclusively, this study demonstrates the in vivo biocompatibility of PEI implants, with favourable properties of electrospun PEI scaffolds regarding tissue integration and wound healing.}, language = {en} } @article{RuederSauterKratzetal.2013, author = {R{\"u}der, Constantin and Sauter, Tilman and Kratz, Karl and Haase, Tobias and Peter, Jan and Jung, Friedrich and Lendlein, Andreas and Zohlnh{\"o}fer, Dietlind}, title = {Influence of fibre diameter and orientation of electrospun copolyetheresterurethanes on smooth muscle and endothelial cell behaviour}, series = {Clinical hemorheology and microcirculation : blood flow and vessels}, volume = {55}, journal = {Clinical hemorheology and microcirculation : blood flow and vessels}, number = {4}, publisher = {IOS Press}, address = {Amsterdam}, issn = {1386-0291}, doi = {10.3233/CH-131787}, pages = {513 -- 522}, year = {2013}, abstract = {Polymers exhibiting cell-selective effects represent an extensive research field with high relevance for biomedical applications e.g. in the cardiovascular field supporting re-endothelialization while suppressing smooth muscle cell overgrowth. Such an endothelial cell-selective effect could be recently demonstrated for a copolyetheresterurethane (PDC) containing biodegradable poly(p-dioxanone) and poly(epsilon-caprolactone) segments, which selectively enhanced the adhesion of human umbilical vein endothelial cells (HUVEC) while suppressing the attachment of smooth muscle cells (SMC). In this study we investigated the influence of the fibre orientation (random and aligned) and fibre diameter (2 mu m and 500 nm) of electrospun PDC scaffolds on the adhesion, proliferation and apoptosis of HUVEC and SMC. Adhesion, viability and proliferation of HUVEC was diminished when the fibre diameter was reduced to a submicron scale, while the orientation of the microfibres did only slightly influence the cellular behaviour. In contrast, a submicron fibre diameter improved SMC viability. In conclusion, PDC scaffolds with micron-sized single fibres could be promising candidate materials for cell-selective stent coatings.}, language = {en} } @article{MayerUciechowskiMeyeretal.2014, author = {Mayer, Lena S. and Uciechowski, Peter and Meyer, S{\"o}ren and Schwerdtle, Tanja and Rink, Lothar and Haase, Hajo}, title = {Differential impact of zinc deficiency on phagocytosis, oxidative burst, and production of pro-inflammatory cytokines by human monocytes}, series = {Metallomics : integrated biometal science}, volume = {6}, journal = {Metallomics : integrated biometal science}, number = {7}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1756-5901}, doi = {10.1039/c4mt00051j}, pages = {1288 -- 1295}, year = {2014}, language = {en} } @article{BronnerUtechtHaaseetal.2014, author = {Bronner, Christopher and Utecht, Manuel Martin and Haase, Anton and Saalfrank, Peter and Klamroth, Tillmann and Tegeder, Petra}, title = {Electronic structure changes during the surface-assisted formation of a graphene nanoribbon}, series = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr}, volume = {140}, journal = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr}, number = {2}, publisher = {American Institute of Physics}, address = {Melville}, issn = {0021-9606}, doi = {10.1063/1.4858855}, pages = {7}, year = {2014}, abstract = {High conductivity and a tunability of the band gap make quasi-one-dimensional graphene nanoribbons (GNRs) highly interesting materials for the use in field effect transistors. Especially bottom-up fabricated GNRs possess well-defined edges which is important for the electronic structure and accordingly the band gap. In this study we investigate the formation of a sub-nanometer wide armchair GNR generated on a Au(111) surface. The on-surface synthesis is thermally activated and involves an intermediate non-aromatic polymer in which the molecular precursor forms polyanthrylene chains. Employing angle-resolved two-photon photoemission in combination with density functional theory calculations we find that the polymer exhibits two dispersing states which we attribute to the valence and the conduction band, respectively. While the band gap of the non-aromatic polymer obtained in this way is relatively large, namely 5.25 +/- 0.06 eV, the gap of the corresponding aromatic GNR is strongly reduced which we attribute to the different degree of electron delocalization in the two systems.}, language = {en} } @misc{MayerUciechowskiMeyeretal.2014, author = {Mayer, Lena S. and Uciechowski, Peter and Meyer, S{\"o}ren and Schwerdtle, Tanja and Rink, Lothar and Haase, Hajo}, title = {Differential impact of zinc deficiency on phagocytosis, oxidative burst, and production of pro-inflammatory cytokines by human monocytes}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-99405}, year = {2014}, abstract = {Zinc deficiency has a fundamental influence on the immune defense, with multiple effects on different immune cells, resulting in a major impairment of human health. Monocytes and macrophages are among the immune cells that are most fundamentally affected by zinc, but the impact of zinc on these cells is still far from being completely understood. Therefore, this study investigates the influence of zinc deficiency on monocytes of healthy human donors. Peripheral blood mononuclear cells, which include monocytes, were cultured under zinc deficient conditions for 3 days. This was achieved by two different methods: by application of the membrane permeable chelator N,N,N0´,N0´-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) or by removal of zinc from the culture medium using a CHELEX 100 resin. Subsequently, monocyte functions were analyzed in response to Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. Zinc depletion had differential effects. On the one hand, elimination of bacterial pathogens by phagocytosis and oxidative burst was elevated. On the other hand, the production of the inflammatory cytokines tumor necrosis factor (TNF)-a and interleukin (IL)-6 was reduced. This suggests that monocytes shift from intercellular communication to basic innate defensive functions in response to zinc deficiency. These results were obtained regardless of the method by which zinc deficiency was achieved. However, CHELEX-treated medium strongly augmented cytokine production, independently from its capability for zinc removal. This side-effect severely limits the use of CHELEX for investigating the effects of zinc deficiency on innate immunity.}, language = {en} } @article{WichmannStaudlerHaaseetal.2000, author = {Wichmann, Matthias and Staudler, Holger and Haase, Peter and Burkart, Michael}, title = {Naturschutzfachliche Bewertung einer Pflegemaßnahme mit Galloways am S{\"u}dufer des G{\"u}lper See unter Einfluß hydrologischer Dynamik}, year = {2000}, abstract = {Since 1993 the southern shore of Lake G{\"u}lpe in western Brandenburg has been man-aged with Galloway cattle. This is supported by the so called "Vertragsnaturschutz" (i.e. contract nature conservation) in order to preserve the valuable, species-rich vegetation structure. This is an economically justifiable arrangement for the Galloway cattle-farmer. Permanent botanical plots were monitored in the area for four years. For most species, the observed changes in vegetation are considered as mere fluctuations on the basis of their known ecological requirements and data on hydrological dynamics during the study. Only a few species might indicate succession. A continuation of the present form of land management is recommended for the preservation of the current vegetation structure. However it is advisable to continue with monitoring of the vegetation in order to confirm the results over larger timescales. Until then the management with Galloway cattle is to acclaim as a proper treatment to preserve the southern shore of Lake G{\"u}lpe.}, language = {de} }