Dr. rer. nat. Ansgar Petersen
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Biomaterials for Endogenous regeneration
Guiding structures for bone defect regeneration
Next generation biomaterials are expected to provide a microenvironment that supports cells in their function to repair or even fully regenerate tissue after damage. We use macroporous biomaterial scaffolds that, due to their specific pore architecture, structurally guide the healing process. To improve the performance of these materials we systematically alter material parameters and investigate the resulting cell and tissue response. Our goal is to explore the potential of such materials to support the body`s inherent regeneration capabilities.
Cell organization and Extracellular matrix patterning
Cell organisation and extracellular matrix formation in porous biomaterials
Biomaterials are used clinically to support tissue healing. However, the way tissue forms inside biomaterial pores is not fully understood. The process is often described as a layer-by-layer growth process where cells proliferate and fill the pore from the biomaterial wall to the pore center. However, traction forces generated by the cells strongly influence cell and extracellular matrix (ECM) organization, especially at early stages of tissue formation. We use macroporous collagen biomaterials and simplified 3D structures reproducing the biomaterial's pore architecture to investigate the role of cell forces and tissue contraction on extracellular matrix patterning. Our aim is to understand how a biomaterial's pore architecture can be used to achieve ECM patterns that structurally guide and thereby support tissue regeneration, e.g. in bone or cartilage defects.
Are mechanical or structural properties of the extracellular matrix altered by growth factors?
In contrast to an advanced understanding how Bone Morphogenetic Proteins (BMPs) influence cell behaviour, little is known about their effect on extracellular matrix formation in early stages of tissue regeneration. Using macroporous biomaterials as 3D environments, we investigate the process how primary cells build extracellular matrix in the presence or absence of BMP2. We are specifically interested in BMP2-induced alterations of biochemical and mechanical matrix properties. With this, we aim at a better understanding of alternative ways how BMPs influence bone tissue regeneration next to the chemo-attraction and differentiation of stem cells.
Role of mechanical signals in regeneration
Mechanical loading enhances growth factor signaling
Biochemical signaling via proteins is fundamental for the development of muskuloskeletal tissues but also for their regeneration. Bone Morphogenetic Proteins (BMPs) have proven to be potent inducers of bone formation but potential side effects e.g. ectopic bone formation, currently limit their clinical applications. To reduce risks associated with growth factor therapy, the underlying signaling mechanisms have to be better understood. Interestingly, beside biochemical factors also mechanical signals arising from tissue deformation or fluid flow were found to influence growth factor signaling. In fact, we have shown in collaboration with the Knaus Lab that BMP2 and mechanical loading synergistically promote events in the BMP2 signaling pathway. Based on this finding we currently investigate the underlying molecular mechanism how mechanical forces are integrated into signaling events. Such an understanding would help to develop and improve treatment strategies in which both, mechanical and biochemical, stimuli act cooperatively.