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Fabrication and Surface Engineering of Pu-Tio2 Nanocomposites with Improved Mechanical, Surface and Hemocompatibility Properties with Usability in Vascular Tissue Engineering

Kianpour, Ghazal | 2020

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 53967 (48)
  4. University: Sharif University of Technology
  5. Department: Institute for Nanoscience and Nanotechnology
  6. Advisor(s): Baghery, Reza; Pourjavadi, Ali; Ghanbari, Hossein
  7. Abstract:
  8. The main focus of this project is the fabrication of surface engineering scaffolds based on polyurethane and titanium dioxide. The research's aim is the creation of the synergistic properties of TiO2 and PU as a new strategy for engineering artificial autologous blood vessels. In the first section, PU-TiO2 nanocomposites were synthesized by co-insitu synthesis of nanoparticles and polymer. The nanocomposite films were prepared by solvent casting and thermally induced phase separation methods. Mechanical and biological properties of films were compared with pure PU film. In solvent casting method, the outcomes revealed that the rate of endothelialization of the nanocomposite scaffold after 7 days of in vitro cell culture was 140% compared to the polystyrene plate (positive control). This amount is approximately 1.5 times that of PU scaffolding. By adding 2 wt. % of TNPs, Young's modulus was tripled while the tensile elongation at the break did not change so much and the nanocomposite scaffold had an 800% elongation at the break.In the thermally-induced phase separation, a completely porous scaffold with a porosity of 44.6% was created. In the second section, titanium dioxide nanotubes were electrochemically prepared. By optimizing the electrochemical conditions, titanium dioxide nanotube-polyurethane flexible nanocomposite film was spontaneously detached from titanium underlying. The modulus, elongation at break and the final tensile strength for these films are150 MPa, 881% and 18.5 MPa subsequently. Cell viability at 7 days after cell culture on these scaffolds was 135% compared to the positive control. These scaffolds have closed-end pipes and have a super hydrophilic surface with a contact angle of 9º. In the third section, the closed-ended nanotubes were opened and hydrophilic TNT-PU films were created with a water contact angle of 54º. The cell viability at the 7 days on these scaffolds was 210% compared to the cell culture plate. In the fourth section, the hydrophilic films were transformed into super-hydrophobic films with a water contact angle of 145 º. In the fifth section, the surface was modifying by oxygen gas. Platelet adhesion analysis showed that these scaffolds have a 98% reduction in the number of platelets adhesion compared to pure PU scaffolds
  9. Keywords:
  10. Polyurethane ; Porosity ; Flexibility ; Artificial Vessels ; Tissue Engineering ; Titanium Oxide

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