Intervertebral disc tissue engineering is challenging because it involves the
integration of multiple tissues with distinct structures and compositions such as
lamellar annulus fibrosus, gel?like nucleus pulposus and cartilage endplate. Each
of them has different compositions and different structures. It is hypothesized
that integration of tissues can be enhanced with appropriate mechanical and
biological stimuli. Meanwhile, effect of torsional stimulus on cell re?orientation
in mesenchymal stem cell?collagen tubular constructs is investigated in this study.
Furthermore, it is proposed that these findings can be used to fabricate a multicomponent
unit for intervertebral disc tissue engineering. It has been
demonstrated that mechanical and biological stimuli can stabilize the interface
between osteogenic and chondrogenic differentiated constructs with enhanced
ultimate tensile stress while the phenotype of osteogenic and chondrogenic
differentiated constructs were maintained. Scanning electronic microscopic
images have shown aligned collagen fibrils and presence of calcium at the
interface, indicating the possibility of the formation of a calcified zone. In
addition, it is proven that torsional stimulus triggered re?orientation of
mesenchymal stem cells in collagen lamellae towards a preferred angle. Cell
alignments were confirmed by using a MatLab?based program to analyze the
actin filament and the cell alignment via Phalloidin and Hematoxylin staining,
respectively. Cells and actin filaments were inclined around 30o from the vertical
axis, while cells and filaments in the control group (static loading) aligned along
the vertical axis. Furthermore, a double?layers bioengineered unit was fabricated,
with intact osteogenic differentiated parts at both ends. Comparatively higher
cell density was observed at the interface between layers, demonstrating the
interactions between layers, while the phenotype of each part was maintained in
14 days culture. This study concludes that a multi?components bioengineered
unit with preferred cell alignments can be fabricated. This provides new insights
to future development of bioengineered spinal motion segment for treating late
stage disc degeneration. / published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy
| Identifer | oai:union.ndltd.org:HKU/oai:hub.hku.hk:10722/174502 |
| Date | January 2012 |
| Creators | Chik, Tsz-kit., 戚子傑. |
| Contributors | Chan, BP, Sze, KY |
| Publisher | The University of Hong Kong (Pokfulam, Hong Kong) |
| Source Sets | Hong Kong University Theses |
| Language | English |
| Detected Language | English |
| Type | PG_Thesis |
| Source | http://hub.hku.hk/bib/B47849447 |
| Rights | The author retains all proprietary rights, (such as patent rights) and the right to use in future works., Creative Commons: Attribution 3.0 Hong Kong License |
| Relation | HKU Theses Online (HKUTO) |
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