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Fluorescent microscope image of tyrosine- derived polycarbonate nerve conduit
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Graduate student Mindy Ezra, MS using microscopy to study neuronal cellular behavior on various polymeric substrates |
Following peripheral nerve injury, neurons can regenerate; however, there is poor functional recovery due to their limited ability to transverse long gaps and reconnect with their distal targets. Therefore, there is a need to guide regeneration in order to increase functional recovery following injury. In the past decade, tubulization has become a popular method to repair severed nerves as it allows factors and cells to remain in direct contact with the nerve, provides direction, and protects the wound space. A hollow tube or conduit can be used to bridge together small nerve gaps, <10 mm, but a more complicated internal architecture is necessary to help guide peripheral nerve regeneration for larger nerve gaps. To successfully foster nerve regeneration in critically large gaps,the Kohn Lab fabricates a biodegradable, polymeric scaffold using tyrosine-derived polycarbonates that provides physical and biologic guidance (by means of a peptide mimic) to regenerating nerves, directing the nerve on where to navigate. These scaffolds are assessed for their ability to accelerate regeneration of the femoral nerve in mice. Following implantation, scientists perform functional analysis in order to evaluate muscle function during the walking cycle. Moreover, individual axons are also identified in order to determine whether or not the nerves reconnected properly. From these performance outcomes, the polymer composition used for this application can be further optimized and the design of the scaffold improved to enhance regeneration.
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Figure a. Scanning electron micrograph of cross-section of porous conduite Figure b. Mouse femoral nerve injury model used to evaluate nerve conduit's performance Image shows division of the femoral nerve into two separate branches, a motor branch and a sensory branch Figure c. Placement of conduit in the mouse model. Inlay shows actual conduit dimensions
Project Leader: Mindy Ezra, MS Funding Source: CeMBR / Center for Military Biomaterials Research, (DoD grant W81XWH-04-2-0003)
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