02. Master's Thesis

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Browsing 02. Master's Thesis by Subject "3D-Printing"

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    A DOUBLE-CROSS LINKING APPROACH FOR HIGH FIDELITY 3D-PRINTING OF CELL-LADEN SCAFFOLDS FOR BONE REGENERATION
    (School of Engineering and Digital Sciences, 2023) Shehzad, Ahmer
    Introduction: Artificial organ development, especially bone, is considered a challenging and complicated procedure in tissue engineering, which finds its application in eliminating animal trials and alternative ways to overcome the scarcity of organ donors and avoid host transplant rejection. Bone injury recovery mechanisms are usually longer and more complicated. Traditional clinical treatments such as bone grafts are considered nowadays for efficient recovery mechanisms. However, host rejection and infection proliferation resulted in an unsatisfactory recovery mechanism. Biopolymers are highly biocompatible and have tunable mechanical properties for bone regeneration applications. Biomaterials provide the interconnected porous structure that mimics the native bio-environment, governs the extracellular matrix, and facilitates bone tissue formation. Optimization of shear thinning properties contributes to the fabrication of high-fidelity scaffolds via extrusion-based bioprinting. A high-fidelity scaffold promotes cell proliferation and cues extracellular matrix, which corresponds to aligned collagen fiber. Method: Here, we proposed various blends of hydrogel composite such as %Algiante/%Gelatin/%GelMA ranges from I (1/4/5), II (1/8/2.5), and III (1/2/10), respectively, to produce high fidelity mesenchymal stem cell-laden scaffold with excellent cell viability, characterized by rheological analysis, scanning electron microscopy(SEM), nuclear magnetic resonance(NMR) spectroscopy and confocal microscopy respectively. The double crosslinking approach was utilized , i.e., ionic crosslinking of alginate polymer with calcium ions and covalent bonding between GelMA chains mediated by UV irradiation in the presence of LAP photoinitiator, provided strong mechanical properties which enhance the biodegradability. Result: The scaffold obtained with various porosity and pore sizes ranges from 50 to 120 µm and high printing accuracy up to 95%, which promoted cell adhesion, proliferation, and migration, and facilitated cell differentiation and tissue development. The scaffold with a low concentration of GelMA ranging from 2.5 to 5 % demonstrated high cell viability and Alkaline Phosphatase (ALP) activity, demonstrating the presence of osteocytes. Alizarin Red, H&E, and Masson Trichrome staining depict calcium deposition, extracellular matrix, and collagen fiber. Conclusion: Based on the excellent cytocombaitbility and proliferation rates, the reported hydrogel construct will be used in the development in vitro bone organoids. These scaffold model not only useful for bone regeneration but also finds its application in other tissue engineering application