Cells respond not only to biochemical but also to physical cues, such as stiffness, geometry and matrix degradability. In-vitro studies showed that hydrogel elasticity or degradation properties alone can direct cell differentiation, while scaffold geometry can control tissue growth rate. However, little is known about how these findings translate to an in-vivo scenario. Bone defect healing experiments were used to investigate how the architecture of a semi-rigid scaffold may pattern the organization of collagen fibers and subsequent mineralization in-vivo, using a 30 mm critical-sized defect in sheep tibia as a model system. The hierarchical material structure and properties of regenerated tissue were investigated using a multi-scale and multi-modal approach. Next, alginate hydrogels with varying stiffness were used for in-vivo host cell recruitment and osteogenic differentiation in a rat femoral 5 mm critical-sized defect. Current activities focus on tailoring the spatio-temporal degradation properties of novel click-crosslinked alginate hydrogels to direct cell migration and proliferation, guide spatial distribution and directionality of extracellular matrix deposition, and pattern in-vivo tissue formation.
Amaia Cipitria, PhD, got her Ph.D. in Materials Science and Metallurgy at the University of Cambridge, UK, in 2008. She worked as a postdoctoral researcher at Queensland University of Technology, Brisbane, Australia, and at the Charité University Hospital Berlin, Germany. In 2011 she became a principal investigator at the Charité University Hospital Berlin, investigating the effect of biomaterial physical properties, such as stiffness, geometry or degradation properties, on cell response and in-vivo bone regeneration, using small and large animal models. She applies advanced materials characterization techniques to investigate tissue hierarchical structure at different length scales and its biological function. In 2017 she moved to the Max Planck Institute of Colloids and Interfaces, Potsdam, Germany, as an Emmy Noether group leader. Her current research is focused on how biophysical mechanisms regulate cell-matrix interaction in tissue regeneration, cancer dormancy and bone metastasis.