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Title Promotion of the osteogenic differentiation of pre-osteoblastic cells in piezoelectric porous scaffolds under mechanical stimulation
Alternative Title Αύξηση της οστεογενούς διαφοροποίησης προ-οστεοβλαστών σε πιεζοηλεκτρικά πορώδη ικριώματα με χρήση μηχανικής διέγερσης
Author Ταβερναράκη, Νικολέτα Ναταλία
Thesis advisor Χατζηνικολαϊδου, Μαρία
Reviewer Βαμβακάκη, Μαρία
Abstract Bone is a highly dynamic tissue that undergoes continuous mechanical forces throughout life.Mechanical stimuli applied on scaffolds resembling a part of the human bone tissue could have major effect on osteogenesis. However, the precise conditions governing this process remain largely unexplored.Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is a piezoelectric material that responds to mechanical stimulation, producing an electrical signal that promotes the osteogenic differentiation of pre-osteoblastic cells by opening voltage-gated calcium channels. The aim of this study was to examine the biological behavior of mouse calvaria osteoblastic precursor cells (MC3T3-E1) when seeded onto lyophilized piezoelectric PEDOT:PSS-containing scaffolds applying uniaxial compression. Two differentconcentrations of PEDOT:PSS(0.15% w/v and 0.10% w/v) were combined with a 5% w/v poly(vinyl alcohol) (PVA) and 5% w/v gelatin, casted into wells, freeze dried and crosslinked with 2% v/v (3-glycidyloxypropyl)trimethoxysilane (GOPS) and 0.025% w/v glutaraldehyde. The scaffolds were physicochemically characterized by Fourier transform infrared spectroscopy (FTIR), measurement of elastic modulus, swelling ratio, degradation rate. Scaffolds seeded with pre-osteoblastic cells were subjected to uniaxial compression with a frequency of 1 Hz and a strain of 10% for 1 h daily for 21 days, and their osteogenic response was compared to that of a non-mechanically stimulated culture, the static one. The loading parameters were selected to resemble thein vivo loading situation. Cell viability and morphology of the MC3T3-E1 pre-osteoblasts seeded on the PEDOT:PSS/PVA/gelatin scaffolds were determined. The alkaline phosphatase (ALP) activity, the collagen and calcium production were assessed to validate the effect of the piezoelectric scaffolds in presence (dynamic culture) and in absence (static culture) of the mechanical stimuli towards the osteogenic differentiation process of the pre-osteoblasts.PEDOT:PSS/PVA/gelatin scaffolds presented favorable mechanical properties for bone tissue engineering.Their elastic modulus ranged between 1 and 5 MPa. The degradation rates indicate a mass loss up to 15% after 21 days.The cell viability indicates an increase of cell number over time, whilescanning electron microscopy (SEM) imagesdisplaywell-spread cells morphology. The ALP activity at days 3 and 7 is higher in the dynamic culture compared to the static one. Increased ALP activity and profound collagen and calcium secretion further validate osteogenic response. Moreover, energy dispersive spectroscopy (EDS) analysis revealed the presence of calcium phosphate in the extracellular matrix after 21 days. Our results indicate that the PEDOT:PSS/PVA/gelatin scaffolds support the adhesion, proliferation, and osteogenic differentiation of the pre-osteoblastic cells under mechanical stimulation, thus favoring bone and other load-bearingtissue engineering with amplified matrix production. Furthermore, the development of a comprehensive 3D mechano-active model, establishes an innovative platform for studying osteogenesis under conditions closely resembling the body natural state. This approach not only contributes to advancing in vitro evaluation methods but also significantly reduces the need for in vivo experimentation.
Language Greek
Issue date 2023-11-29
Collection   School/Department--School of Sciences and Engineering--Department of Materials Science and Technology--Graduate theses
  Type of Work--Graduate theses
Permanent Link https://elocus.lib.uoc.gr//dlib/6/8/a/metadata-dlib-1702367759-982860-8982.tkl Bookmark and Share
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