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Nano-composite Conduits with Piezoelectric Properties and Hydrogel as the Luminal Filler for Regeneration of Peripheral Nerve Traumas

Tavakoli, Amir Hossein | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54963 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Ramazani Sadatabadi, Ahmad
  7. Abstract:
  8. This article investigates the production of a novel nerve regeneration scaffold by using biodegradable and biocompatible components. In this research, we have provided different methods like electrospinning and PE hydrogels to fabricate it. Electrospun fibers are made of PLLA and CS/Gel combinations. ZnO nanoparticles were used as the piezoelectric agent. Piezoelectricity plays an important part in the strcture of neurons giving them the ability to transfer electrical messages throughout the body. NPs were completely dispersed in the PLLA solution. ZnO particles could increase produced voltages as the concentration increases. PLLA is biodegradable and provide good mechanical properties. CS/Gel layer is in charge of cell adhesion and preparaing a proper environment for cell growth. The electrospun fibers are manufactured using a double-nozzled system. The size of fibers are in the magnitude of 100 nm. Finally, the fibers were exposed to vapor of glutaraldehyde to chemically make linkages. This phenomenon could greatly enhance mechanical properties of the scaffold. This layer also favors the hydrophilicity of the fibers. Also this type of conduit benefits from another crucial part which is the luminal filler. This is an aerogel which has the responsibility of transferring neccessory materials like growth factors and cells into the conduit. Many researches have also proved that using luminal filler can guide and improve axonal growth if implemented properly. This hydrogel is composed of chitosan and NaCMC that can form a physical network between positively charged groups of chitosan and carboxyl groups of NaCMC. This hydrogel is thermosensitive and pH sensitive. We measured gelation time of the aforementioned hydrogel. After injecting luminal filler into the rolled fibers, the fabricated conduit gets freeze-dried. This process change the inside hydrogel into an aerogel. Good pore shape and permeability would help axonal growth. At the end, the final samples were prepared adding CNT to provide conduction into hydrogel formulation and they were tested to analyze their welling ratios and biodegradation rates. The samples could be sufficiently stable in PBS solution. They were monitored for 3 weeks. Keeping the whole process, we could conclude that this method is very reasonable in the case of processibilty, ease and implementation and they could show tangible properties. Based on in-vitro calculations, there is a great chance for implanting these samples in real cases and inverstigating in-vivo parameters
  9. Keywords:
  10. Piezoelectric ; Hydrogel ; Fibers ; Nanoparticles ; Electrospinning ; Retrofiting ; Peripheral Nerve Injury

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