concept microstructures were fabricated of SU-8 negative photoresist (MicroChem, Germany). Interaction of cells with structures of different sizes and shapes was investigated by culturing human mesenchymal stem cells (hMSCs) at different concentrations with varying number of structures. The number of structures that were assembled into aggre-gates and the compaction of the aggreaggre-gates were monitored over time. Aggregates showed more circularity and higher aggregation speed when cells were cultured on smaller structures or on more hydrophilic structures. By controlling cell attachment sites, this bottom-up approach could be applicable to the fabrication of 3D cell-laden con-structs as carriers for systemic cell delivery or as self-assembled scaf-folds for tissue constructs of clinical relevant sizes.
34.P08
Mechanical properties of self-assembling peptide
hydrogels and their effects on cell behaviors
G Cinar, H Ceylan, AB Tekinay and MO Guler*
Institute of Materials Science and Nanotechnology, National
Nanotechnology Research Center (UNAM), Bilkent University,
Turkey
Development of self-assembling biomimetic molecules and integration of those in materials for tissue engineering is one of the most interest-ing research areas in materials science. Our research is aimed to study self-assembling peptides and understand possible non-covalent interac-tions taking place in self-assembly mechanisms such as hydrogen bonds, electrostatic and hydrophobic interactions in aqueous condi-tions. In this work, the non-covalent interactions between oppositely charged peptides are investigated experimentally and simulation of possible aggregate formations is demonstrated. Development of a new peptide hydrogels with interesting mechanical properties and with low contamination risk is one of the main targets of this research. We aim to highlight concentration and time dependence of peptide hydrogels and understand the relationship between mechanical properties and bioactive parameters. We also focus on biocompatibility and biodegrad-ability of the designed hydrogels, which have great potentials for appli-cations in regenerative medicine.
34.P09
In situ chondrogenic differentiation of bone
marrow stromal cells in bioactive self-assembled
peptide gels
Y Jung, JE Kim and SH Kim
Korea Institue of Science and Technology, South Korea
The gradual increase in the aging population has resulted in many osteoarthritis patients. However, articular cartilage is a specific tissue which lacks nerves and blood vessels and has limited self-repair abili-ties. Recently, there are many studies on peptide hydrogel scaffolds which are biocompatible and low immunogenic for cartilage tissue engineering. In this study, we used self-assembled peptide gels having unique peptide sequences and introduced the bioactive motifs to the end of the sequences of peptide gels, which are collagen mimetic pep-tides (CMPs). CMPs that have a unique collagen-like triple helical con-formation have been shown to associate with collagen molecules and fibers via a strand invasion process. In order to examine the in situ chondrogenic differentiation of rabbit bone marrow stromal cells (rBMSCs) by functional motifs, biochemical analysis were conducted. The results showed that the secretion of cartilage specific extra cellular matrix and the gene expression concerned with chondrogenic differen-tiation were increased in group of self-assembled peptide gels intro-duced CMPs motifs. From the results, it was confirmed that CMPs modified self-assembled peptide gels could enhance effectively the chondrogenic differentiation in situ, consequently they could be a good scaffold for cartilage tissue engineering.
34.P10
Catechol-driven layer-by-layer assembly for
surface hydrogel coating
TG Kim
Severance Hospital Integrative Research Institute for Cerebral &
Cardiovascular Diseases, Korea
Surface engineering of materials can introduce the preferable function-ality by physical, chemical, or biological decoration into the elaborated architecture having inert exterior, which can boost the end role of the consequent product in a wide range of areas. Due to processing limita-tion of funclimita-tional materials in produclimita-tion, bulk material manufacturing with subsequent surface modification of interesting species is often desirable. In particular, surface modification with hydrogels has unique advantages of a high degree of hydrophilicity and biocompatibility in the context of biomedical applications. In this study, we devised the novel layer-by-layer assembly using mussel adhesive-inspired driving force, which led to spontaneous formation of surface-bound hydrogel on virtually all types of substrates including plastics, metals, and ceramics. First, we synthesized many types of catechol-polymer conju-gates through simple EDC chemistry. The catechol-polymer conjuconju-gates was sequentially adsorbed on the substrate by layer-by-layer fashion with each subsequent oxidation of catechol groups. The resulting hy-drogel on the substrate exhibited anisotropic swelling and tenacious adherence to various substrates. This surface-bound hydrogel has promising potential for biomedical applications such as local drug res-ervoir, biocompatible coating, and protective lubricious surface layer.
34.P11
Modular adipose tissue engineering for soft
tissue reconstruction
TG Kim
Severance Hospital Integrative Research Institute for Cerebral &
Cardiovascular Diseases, Korea
Adipogenic tissue reconstruction or augmentation has been imple-mented when complex trauma, oncologic resections, and congenital or acquired deformities often associated with massive loss of adipose tis-sue are accompanied. Currently, the transplantation of autologous fat tissue is the main clinical modality for rehabilitating the defect sites. However, the lack of sufficient vascularization after transplantation causes significant graft volume shrinkage, resulting in poor long-term clinical success. Here, we demonstrate a multiscale (from nanometer-scale to macro-nanometer-scale) and multifunctional assembly route to hierarchi-cally mimic 3D adipose tissue. Biologihierarchi-cally optimized module tissues were used as building units for fabricating 3D biohybrid construct of higher order. The microstructured scaffold was prepared via a DPMD process and allowed to deliver angiogenic growth factor in a sustained manner. These bioactive scaffolds with periodic porous internal struc-tures were used to assist the 3D hierarchical assembly of the composite module tissues. The produced multiscaled and multifunctional modu-lar tissue construct enable the successful formation of vascumodu-larized adi-pose tissue in vivo.
34.P12
Void filling strategies of fibroblasts in the onset
of regeneration
P Joly, A Petersen and G Duda
Julius Wolff Institute, Charite´ - Universita
¨tsmedizin Berlin,
Germany; Berlin-Brandenburg School for Regenerative Therapies,
Charite´, Germany
In regeneration, strategies are identified to fast and effectively fill voids. Fibroblasts are the cells paving the ground for later
reconstitu- 2012 The Authors J Tissue Eng Regen Med 2012; 6 (Suppl. 1): 1–429.
Journal of Tissue Engineering and Regenerative Medicine 2012 John Wiley & Sons, Ltd. DOI: 10.1002/term.1586 34. Multi-scale and Hierarchical Scaffolds and Self Assembly Systems (in coop. Expertissues)
