| Summary: | 博士 === 國立臺灣大學 === 醫學工程學研究所 === 94 === For fabricating functional nerve conduits, we have developed a method using longitudinally oriented channels within biodegradable polymers, chitosan and ploy (d,l-lactide-co-glycolide) (PLGA), created by a combined lyophilizing and wire-heating process. This high permeability and the characteristic porous structure of chitosan scaffold provide increased area to support and guide extending axons subsequent to nerve injury. Utilizing Ni-Cr wires as mandrels to create channels in scaffold increased safety, effectiveness, and reproducibility. Regulating the size and quantity of the Ni-Cr wired allow us to control the number, diameter and pattern of the channels. Furthermore, the techniques can be easily tailored to other solvent and polymer systems.
Fast proliferation of large numbers of schwann cells (SCs) in a short time appears to be promising for stimulating nerve regeneration. Good attachment is a prerequisite for the SCs to survive. Laminin, the extracellular matrix protein, is a permissive protein for SCs adhesion used in neural regrowth. The aim of this study was to investigate the surface effects of laminin coated PLGA and Chitosan membranes after chemical method and plasma treatment. Our results indicated that oxygen plasma is indeed a better method to incorporate laminin onto the surface of membrane. Laminin coated Chitosan membrane significantly increases SCs attachment and affinity for directing nerve regeneration.
To better direct repair following spinal cord injury (SCI), we designed a porous chitosan nerve conduit (NC) created by lyophilizing and wire-heating process, and then incorporated with laminin (LN) on the inner surface by oxygen plasma treatment. To preserve the microstructure of the scaffold, prolonging plasma treatment time was unsuitable. Implantation of the laminin coated nerve conduit (LN-NC) into an adult rat hemisection model of SCI indicated the tendency of behavior improvement. Histology and immunocytochemical analysis suggested that the NCs could lead the damaged axons crossing through the lesion area, but not trigger inflammation or apoptosis. Together with significantly enhanced local GAP-43 expression evidenced by western blot analysis, we found functional recovery mediated by LN-NCs compared better than NCs alone.
For optimizing nerve regeneration through nerve conduits, microenvironment mimicking biological situation is a vital issue. We use microcontact printing (μCP) technique to pattern the bio-molecule, laminin, on the chitosan film surface. Patterned laminin affect the alignment and morphology of Schwann cells. The microcontact printing provides a suitable micro- or nano-scale biological and topological control for cell attachment and outgrowth. This technique is straightforward and convenient for cell-recognition molecules to be micropattern-bound onto the scaffold for tissue regeneration.
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