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جلسه دفاعیه رساله دکتری آقای غفار کاره |
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| | تاریخ ارسال: 1400/12/2 | |
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دفاعیه دکتری در دانشکده شیمی
آقا /غفار خیرالدین کاره/ دانشجوی دکتری شیمی، در تاریخ ۱۴۰۰/۱۲/۴ از رساله دکتری خود تحت عنوان" ساخت داربست PAN حاوی نانو آلیاژ PtAuAg برای تمایز استخوانی سلول‌های بنیادی مزانشیمی " با راهنمایی خانم دکتر آزاده تجردی دفاع خواهدکرد.
استاد راهنمای اول: خانم دکتر آزاده تجردی
استاد مشاور: آقای دکتر موسی کهتری
هیات داوران:
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آقای دکتر سعید دهقانپور فراشاه / مدعو خارجی/
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آقای دکتر محمد مهدی خانی / مدعو خارجی/
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آقای دکتر رحمت اله رحیمی / مدعو داخلی /
- ۴- خانم دکتر فرانک منطقی /مدعو داخلی /
این جلسه ساعت ۱۰ صبح روز ۴/۱۲/۱۴۰۰ در کلاس /۳/ دانشکده شیمی برگزار خواهد شد.
Abstract
Background:
Today, the use of stem cells and different nano-scaffolds (containing different mineral compounds) in stem cell differentiation is considered as a therapeutic strategy. The purpose of this project was to fabricate and characterize alloy nanoparticle powder (binary and ternary) and alloyed polyacrylonitrile nano-scaffold fibers, containing binary alloy particles (M′ M″ PAN NFs) and containing tertiary alloy particles (M′ M″ M‴ PAN NFs. Then, the effect of alloyed nano-scaffold (M′ M″ M‴ PAN NFs), which contain different amounts of constituent metals of Pt, Au and Ag, on the proliferation, growth, metabolic activity, and bone differentiation activity of mesenchymal stem cells in in-vitro conditions was examined.
Materials and methods:
In an experimental study, nanoparticles of binary and ternary alloys were fabricated by environmentally friendly method (ultrasonic method) using green solvent. The polymer solution was heated at ۷۵ ° C for ۱۸ hours in order to modify the polymer structure and create a ring structure riched with the functional groups. The alloy particles were then loaded on electrospun polyacrylonitrile nanofibers. Physicochemical, mechanical, wetting and biological properties of alloyed nano-scaffolds were evaluated by X-ray diffraction, microscopes (scanning, transmission and atomic), FT-IR, water contact angle measurements, tensile, MTT, alkaline phosphatase, mineralization, alizarin and gene expression.
Findings:
In the present study, all synthesized fibrous scaffolds were prepared at the nanoscale. The physicochemical properties of alloyed scaffold structures have been carefully investigated. The results of physicochemical characterization showed that changes in crystalline properties, morphology, structure and stability, mechanical properties and hydrophilicity of the polymer matrix occurred with changes in the type of alloy nanoparticles. Morphological studies of the of all synthesized scaffolds showed that the morphology and roughness of their surfaces were different by creating a three-dimensional space, which was due to differences in the shape of the alloy particle pieces and their distribution on the scaffolding surface. Furthermore, Small-scale alloy nanoparticles were uniformly distributed on the outer surface of the scaffold of the polyacrylonitrile nanofibers “PAN NFs”, leading to formation of wrinkled outer surface. While, the large-scale alloy particles were located on the inner surface of the PAN NFs scaffold. Because the structural properties (crystallinity, surface morphology, roughness and mechanical/hydrophilicity) of the alloyed scaffolds (M′ M″ M‴ PAN NFs) were better than other scaffolds, thus, the differentiation of stem cells on their surface was assessed. Cellular experiments for these scaffolds confirmed a dramatic increase in growth, proliferation, and differentiation of mesenchymal stem cells into bone cells on alloyed nano-scaffolds (M′ M″ M‴ PAN NFs) compared to scaffolds (PAN NFs). Bioavailability, cellular matrix mineralization, calcium level, alkaline phosphatase activity and expression levels of genes (Runx۲, ALP, Col (I), osteocalcin and osteonectin) in mesenchymal stem cells cultured on these nano-alloyed scaffold in days (۷, ۱۴ and ۲۱) have increased significantly. This increase in dose-dependent behaviour of the constituent metals (Pt, Au and Ag) was compared with the control group and the non-alloy scaffold group (PAN NFs). It is likely that this increase in the osteogenic differentiation process of mesenchymal stem cells is also mediated by activation of the interaction (cell-scaffold surface). According to all the results of this study, Pt۲Au۱Ag۱ (first), Pt۱Au۲Ag۱ (second) and Pt۱Au۱Ag۲ (third) can be valuable osteogenesis factors in inhibiting cell death, increasing cell proliferation and survival. As a result, it was used in advanced cell therapy and tissue engineering technologies.
Conclusion:
In addition to the morphological differences of the alloyed fibrous scaffolds (M′ M″ M‴ PAN NFs), the amount of calcium, the activity of the alkaline phosphatase enzyme and the metabolic activity of the osteoblasts are different from each other. Therefore, in addition to Alizarin staining S, the factors mentioned in this study can be used to detect in-vitro differentiation of mesenchymal stem cells into osteoblasts. Because they have excellent ossification capabilities, they will be useful in restorative medicine to regenerate bone tissue.
Keywords:
Nano-alloy, Nanofibers, Electrospinning, Ultrasound, Structural properties, Bone alloyed-scaffold, Mesenchymal stem cells, Bone differentiation of cells
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