טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentHaj Josephina
SubjectHybrid Scaffold Imitating ECM Seeded with MSCs for Bone
Regeneration
DepartmentDepartment of Medicine
Supervisor Assistant Professor Sarouji Samer
Full Thesis textFull thesis text - English Version


Abstract

While biologically feasible, bone repair is often dissatisfactory, particularly in the cases of large defects. The search for effective bone regeneration strategies has led to the emergence of bone tissue engineering (TE) techniques, which are applied in order to develop biological tissue/organ substitutes that can restore, maintain, or improve function of pathological tissues/organs. In tissue engineering, electrospinning has emerged as a mainstay due to its versatility in fabricating randomly oriented or aligned fibers that are characteristic of the extracellular matrix (ECM). Use of electrospinning has led to the production of scaffolds composed of the polymer nanofiber mats with osteoconductive ceramics.  In parallel, mesenchymal stem cells (MSCs) are capable of both self-renewing and differentiating into numerous tissue types, such as bone, cartilage and fat. Therefore, they have been suggested to be a suitable option for cell-based tissue engineering therapies.

The objective of this work is to create a novel biocompatible hybrid scaffold composed of electrospun polymeric nanofibers combined with osteoconductive ceramics, loaded with human MSCs, to yield a tissue-like construct applied as an implant for in vivo bone formation.

Our scaffold is constructed of nanofibers and ceramic particles, dispersed over the nanofibers during the electrospining process. Human adipose tissue-derived MSCs were isolated, expanded in medium containing osteogenic reagents and characterized by flow cytometry analysis. Prior to MSCs loading on the scaffold, the osteogenic characteristics of the MSCs were validated. 

The cell-embedded scaffolds were characterized by SEM and by Hematoxylin and Eosin (H&E) and Masson's Trichrome staining methods, which demonstrated the MSCs viability and integration into the electrospun nanofibers.

For determining the osteogenic potential of the cell-embedded scaffolds, they were subcutaneously implanted in the dorsal side of mice and tissue samples of the construct area were extracted for histological analysis 8 weeks post-implantation.

Our results suggest that the fabricated hybrid scaffold has exhibited a 3D meshed structure comprised of nano- and macro- architecture, which mimics both levels (nano- and macro-) of ECM in the bone . Furthermore, this scaffold provides an inductive adhesion base for cell matrix and cell-cell interactions, and accelerates osteogenic differentiation via the ceramic particles and the osteogenic factors.