TY  - JOUR
A1  - Castilho, Miguel
A1  - Hochleitner, Gernot
A1  - Wilson, Wouter
A1  - van Rietbergen, Bert
A1  - Dalton, Paul D.
A1  - Groll, Jürgen
A1  - Malda, Jos
A1  - Ito, Keita
T1  - Mechanical behavior of a soft hydrogel reinforced with three-dimensional printed microfibre scaffolds
JF  - Scientific Reports
N2  - Reinforcing hydrogels with micro-fibre scaffolds obtained by a Melt-Electrospinning Writing (MEW) process has demonstrated great promise for developing tissue engineered (TE) constructs with mechanical properties compatible to native tissues. However, the mechanical performance and reinforcement mechanism of the micro-fibre reinforced hydrogels is not yet fully understood. In this study, FE models, implementing material properties measured experimentally, were used to explore the reinforcement mechanism of fibre-hydrogel composites. First, a continuum FE model based on idealized scaffold geometry was used to capture reinforcement effects related to the suppression of lateral gel expansion by the scaffold, while a second micro-FE model based on micro-CT images of the real construct geometry during compaction captured the effects of load transfer through the scaffold interconnections. Results demonstrate that the reinforcement mechanism at higher scaffold volume fractions was dominated by the load carrying-ability of the fibre scaffold interconnections, which was much higher than expected based on testing scaffolds alone because the hydrogel provides resistance against buckling of the scaffold. We propose that the theoretical understanding presented in this work will assist the design of more effective composite constructs with potential applications in a wide range of TE conditions.
KW  - biomedical engineering
KW  - biomedical materials
KW  - gels and hydrogels
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-222280
VL  - 8
ER  - 
TY  - JOUR
A1  - Rödel, Michaela
A1  - Baumann, Katrin
A1  - Groll, Jürgen
A1  - Gbureck, Uwe
T1  - Simultaneous structuring and mineralization of silk fibroin scaffolds
JF  - Journal of Tissue Engineering
N2  - 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.
KW  - Brushite
KW  - calcium phosphate
KW  - cryostructuring
KW  - hydrogel
KW  - mineralization
KW  - silk fibroin scaffolds
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226427
VL  - 9
ER  - 
TY  - JOUR
A1  - Weis, Matthias
A1  - Shan, Junwen
A1  - Kuhlmann, Matthias
A1  - Jungst, Tomasz
A1  - Tessmar, Jörg
A1  - Groll, Jürgen
T1  - Evaluation of hydrogels based on oxidized hyaluronic acid for bioprinting
JF  - Gels
N2  - In this study, we evaluate hydrogels based on oxidized hyaluronic acid, cross-linked with adipic acid dihydrazide, for their suitability as bioinks for 3D bioprinting. Aldehyde containing hyaluronic acid (AHA) is synthesized and cross-linked via Schiff Base chemistry with bifunctional adipic acid dihydrazide (ADH) to form a mechanically stable hydrogel with good printability. Mechanical and rheological properties of the printed and casted hydrogels are tunable depending on the concentrations of AHA and ADH cross-linkers.
KW  - biofabrication
KW  - bioprinting
KW  - hyaluronic acid
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-197600
SN  - 2310-2861
VL  - 4
IS  - 4
ER  -