@article{RoedelTessmarGrolletal.2019, author = {R{\"o}del, Michaela and Teßmar, J{\"o}rg and Groll, J{\"u}rgen and Gbureck, Uwe}, title = {Tough and Elastic alpha-Tricalcium Phosphate Cement Composites with Degradable PEG-Based Cross-Linker}, series = {Materials}, volume = {12}, journal = {Materials}, number = {53}, doi = {10.3390/ma12010053}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226437}, pages = {1-20}, year = {2019}, abstract = {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.}, language = {en} } @article{RoedelBaumannGrolletal.2018, author = {R{\"o}del, Michaela and Baumann, Katrin and Groll, J{\"u}rgen and Gbureck, Uwe}, title = {Simultaneous structuring and mineralization of silk fibroin scaffolds}, series = {Journal of Tissue Engineering}, volume = {9}, journal = {Journal of Tissue Engineering}, doi = {10.1177/2041731418788509}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226427}, pages = {1-16}, year = {2018}, abstract = {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.}, language = {en} }