@misc{NeffevonRuestenLangeBrauneetal.2014, author = {Neffe, Axel T. and von R{\"u}sten-Lange, Maik and Braune, Steffen and L{\"u}tzow, Karola and Roch, Toralf and Richau, Klaus and Kr{\"u}ger, Anne and Becherer, Tobias and Th{\"u}nemann, Andreas F. and Jung, Friedrich and Haag, Rainer and Lendlein, Andreas}, title = {Multivalent grafting of hyperbranched oligo- and polyglycerols shielding rough membranes to mediate hemocompatibility}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-99444}, year = {2014}, abstract = {Hemocompatible materials are needed for internal and extracorporeal biomedical applications, which should be realizable by reducing protein and thrombocyte adhesion to such materials. Polyethers have been demonstrated to be highly efficient in this respect on smooth surfaces. Here, we investigate the grafting of oligo- and polyglycerols to rough poly(ether imide) membranes as a polymer relevant to biomedical applications and show the reduction of protein and thrombocyte adhesion as well as thrombocyte activation. It could be demonstrated that, by performing surface grafting with oligo- and polyglycerols of relatively high polydispersity (>1.5) and several reactive groups for surface anchoring, full surface shielding can be reached, which leads to reduced protein adsorption of albumin and fibrinogen. In addition, adherent thrombocytes were not activated. This could be clearly shown by immunostaining adherent proteins and analyzing the thrombocyte covered area. The presented work provides an important strategy for the development of application relevant hemocompatible 3D structured materials.}, language = {en} } @misc{SchmidtBehlLendleinetal.2014, author = {Schmidt, Christian and Behl, Marc and Lendlein, Andreas and Bauermann, Sabine}, title = {Synthesis of high molecular weight polyglycolide in supercritical carbon dioxide}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-99439}, year = {2014}, abstract = {Polyglycolide (PGA) is a biodegradable polymer with multiple applications in the medical sector. Here the synthesis of high molecular weight polyglycolide by ring-opening polymerization of diglycolide is reported. For the first time stabilizer free supercritical carbon dioxide (scCO2) was used as a reaction medium. scCO2 allowed for a reduction in reaction temperature compared to conventional processes. Together with the lowering of monomer concentration and consequently reduced heat generation compared to bulk reactions thermal decomposition of the product occurring already during polymerization is strongly reduced. The reaction temperatures and pressures were varied between 120 and 150 °C and 145 to 1400 bar. Tin(II) ethyl hexanoate and 1-dodecanol were used as catalyst and initiator, respectively. The highest number average molecular weight of 31 200 g mol-1 was obtained in 5 hours from polymerization at 120 °C and 530 bar. In all cases the products were obtained as a dry white powder. Remarkably, independent of molecular weight the melting temperatures were always at (219 ± 2) °C.}, language = {en} }