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Esmaiel Jabbari of the University of South Carolina presents Synthesis, Fabrication and Modeling of Biomimetic Scaffolds for Skeletal Tissue Regeneration.
Refreshments will be served from 3:30-4:00PM
The seminar will be held 4:00-5:00PM
Seminar Abstract:
Bone is a composite nano-material consisting of an aqueous gel and a mineral phase. The aqueous gel phase gives bone its form and contributes to its ability to resist bending, while the mineral component resists compression. The components of the extra-cellular matrix play multiple coordinated functions during bone formation. For example, osteonectin (ON), a major non-collagenous bone extracellular matrix protein, is involved in several functions including linking of the mineral and collagenous phases, regulation of mineralization, cell motility, and matrix degradation. As another example, matrix metalloproteinases (MMP), secreted by the cellular components, are released to the aqueous gel phase to degrade the collagen network in bone remodeling. In fracture repair, progenitor stromal cells from the periosteum begin to migrate to the site of fracture as a result of degradation of the collagen network by MMP and release of migration factors from the aqueous phase. A tissue engineered synthetic biomaterial as a scaffold for bone regeneration should mimic the complexity of the extra-cellular matrix by providing multiple functions during the course of regeneration. Our hypothesis is that synthetic peptides with multiple biologically active amino acid sequences, separated by inert spacers and covalently attached to degradable scaffolds, can coordinate multiple functions in situ including temporary matrix stability, cell migration and attachment, and matrix degradation.
We have synthesized a functionalized peptide with multiple bioactive amino acid domains including an osteonectin derived apatite-binding domain, an MMP degradable domain, and an integrin-binding RGD domain, to provide structural support and coordinate the processes of cell attachment and matrix degradation. This multifunctional peptide is covalently attached to a synthetic degradable hydrogel/apatite nanocomposite to mimic the elastic and hard phases of the bone matrix. The hydrogel phase is a novel in situ crosslinkable terpolymer poly(L-lactide-co-ethylene oxide-co-fumarate), developed in our laboratory, with building blocks that have excellent biocompatibility. Scaffolds with shape-specific pore geometry are fabricated by micro-printing and fused deposition modeling. Our results demonstrate that the peptide with multiple bioactive domains improves the scaffold
