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Fabrication of Thick Scaffold with Microfluidic Channels by Bioprinter

Khalighi, Sadaf | 2020

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 53033 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Saadatmand, Maryam
  7. Abstract:
  8. Cardiovascular diseases are among the leading causes of death worldwide. For instance, in 2015, almost 31% of the world’s mortality rate was due to these causes. One of these diseases is cardiac coronary vessels’ occlusion which leads to the insufficient blood supply to the heart tissue and cardiomyocytes death after Myocardial Infarction (MI). After MI, a hierarchy of events in the heart tissue changes heart muscle and forms cardiac fibrosis. This fibrotic tissue does not have the native one’s properties and function, so it will cause cardiac arrest and patient death. Therefore, it is obvious that vascular network plays a crucial role in the heart function. The importance of cardiac vascular network is even more because of high energy consumption and also the fact that vessels density in this tissue is 7.5 times higher than other muscle tissues. Fabrication of a scaffold with a prevascular network to resemble native cardiac vessels is one of the regenerative medicine goals. Scientists in tissue engineering work on different ways such as cell incorporation, growth factors addition and extracellular proteins or biophysical stimuli, besides novel microfluidic methods like molding with microneedle or fibers, soft-lithography, photo-patterning, 3D printing and bioprinting to develop a prevascularized scaffold to solve the mass transfer diffusion limitation.In this project, Oxidized Alginate and gelatin which are biocompatible, cell adhesive, and printable materials, are used to develop a novel vascular network structure which is 3D integrated and mimic native network. This scaffold is used to solve nutrient diffusion limitation to the core of scaffold. To form 3D channels in the scaffold, sacrificial gelatin is used which leaves the structure after printing, crosslinking and incubation in 37 °C. Printing parameters and printinbility data are obtained for all experimental groups. Printability in this project is defined as obtaining an acceptable and logical amount for P-value. For each concentration, three different scaffolds are printed with 1 and 3 mm lines, then image analysis from various parts of scaffold is done and P-values are calculated. All the printed scaffolds are fabricated with a pressure lower than 2 bar to avoid applying unusual stress on cells. The scaffolds young’s modulus are about 56.67 KPa which is in good accordance with the native tissue. Channels size are about 700 micrometers and they are lumen like. Also, their interconnectivity and openness evaluated with SEM and micro-CT images
  9. Keywords:
  10. Microfluidic Channels ; Oxidized Alginate ; Sacrificial Reagent ; Bio-Printing ; Artery Stenosis ; Heart Diseases ; Gelatin ; Stroke

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