At present there is an extraordinary need to overcome barriers in regards to
discovering novel and enhanced biomaterials for various tissue engineering
applications. The need for durable orthopaedic implants is on the rise to limit
issues such as revision surgery. A promising pathway to enhance fixation is to
accelerate the onset and rate of early cellular adhesion and bone growth
through nanoscale surface topography at the implant surface. The main aim of
this research project was to investigate cellular response to altered physical
and mechanical characteristics of materials suitable for orthopaedic
applications.
Four injection moulded polymeric substrates were produced, each with varied
compositional and topographical characteristics. The four materials fabricated
are Polyether-ether-ketone (PEEK), PEEK with 30% glass fibre (GL/PEEK)
composite, PEEK and GL/PEEK with grooved topography. SEM and AFM
analysis was used to investigate the groove dimensions and surface
roughness of all samples followed by mechanical testing using a nano indenter
to detect the Young’s modulus, stiffness and hardness of all four substrates.
These tests were performed to determine which material has similar
characteristics to cortical bone. These tests were followed by wettability and
surface energy testing. Cell-substrate adhesion was examined using a cell
viability assay to identify if there is a significant difference (p<0.05) between
the percentage of viable cells on all four PEEK based materials. Imaging of
MG-63 osteosarcoma cells using immunohistochemistry staining kits was
conducted to observe the relationship between cell length and surface
topography followed by a comparison between HaCaT (skin) cells and MG-63
(bone) cells.
Following experimental testing mechanical variations between PEEK and
GL/PEEK were identified alongside physical characterization differences. The
grooved topography increased the surface roughness of PEEK and GL/PEEK
in comparison to the planar surface. After 72 hours a correlation between the
increased surface roughness and the percentage of viable MG-63 cells could
be identified. When assessing the effect surface topography has on the water
contact angles and surface energy, all four substrates showed no correlation.
However, the grooved topography did increase the water contact angle and
reduced the surface energy of PEEK in comparison to planar PEEK. Images
of the four substrates after cell culture observed the grooved topography to
affect the cellular orientation of both MG-63 and HaCaT cells.
Polycaprolactone (PCL) scaffolds with a concentration of 1, 3, and 5%
triclosan (an antimicrobial and antifungal agent) were fabricated using
electrospinning. In addition to PCL + Triclosan scaffolds PCL with a
concentration of 1% silver (an antimicrobial agent that can reduce the risk of
infection) and 1, 3, and 5% triclosan were also electrospun. The pore size and
fibre diameters of the scaffolds were investigated using SEM and Image J
software followed by wettability and surface energy testing. MG-63 cells were
cultured on all PCL scaffolds to study cellular viability percentage after 24 and
72 hours. The findings obtained showed the physical characteristics of PCL
scaffolds to affect cellular viability of MG-63 cells.
The output from these findings aim to provide data at a proof of concept level
in understanding the relationship between the mechanical and physical
characteristics of biomaterials and cellular behaviour.
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/18671 |
| Date | January 2019 |
| Creators | Rehman, Ramisha U. |
| Contributors | Youseffi, Mansour, Sefat, Farshid, Katsikogianni, Maria G. |
| Publisher | University of Bradford, Biomedical and Electronics Engineering Department, Faculty of Engineering and Informatics |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Thesis, doctoral, PhD |
| Rights | <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>. |
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