This study aimed at guiding osteoblast cells on biodegradable polymer carriers
with well-defined surface microtopography and chemistry, and investigating the
effect of cell alignment on osteoblast phenotype expression. A blend of two different
polyesters, one being natural in origin (PHBV) and the other synthetic (P(L/DL)LA),
was used to form a film with parallel macro- (250 µ / m wide) or microgrooves (27 µ / m
wide) on its surface, by solvent casting on patterned templates. The micropatterned
Si template was produced by photolithography, while the Teflo macropatterned template was lathe cut. Fibrinogen (Fb) was adsorbed or
immobilized via epichlorohydrin spacer/crosslinker on the film surfaces to enhance
cell attachment by increasing the surface hydrophilicity and by providing RGD
amino acid sequence for integrin binding. Surface hydrophilicity was assessed by
water contact angle measurements. Adsorption of Fb caused an increase in
hydrophilicity, while the opposite was achieved with its covalent immobilization. Fb
was homogeneously immobilized throughout the whole micropatterned film surface
with amount of 153.1 ± / 42.4 g Fb/cm2, determined with the Bradford assay, while it
was adsorbed within the grooves of the micropattern. Surface characteristics of the
films were studied with Scanning Electron (SEM) and Light microscopy.
Osteoblast cells derived from rat bone marrow were seeded on the polymeric
films with different surface topography and chemistry and were grown for one and
three weeks. Osteoblast proliferation on the films was determined with Cell Titer 96
TM Non-Radioactive Cell Proliferation (MTS) test. Alkaline Phosphatase (ALP)
assay and tetracycline labelling of mineralized matrix were carried out to determine
osteoblast phenotype expression on different surfaces. SEM and fluorescence
microscopy were used to evaluate the cell alignment. Osteoblasts on the
micropatterned films with adsorbed Fb aligned along the groove axis with a mean
deviation angle of 13.1o, while on the unpatterned films deviation from horizontal
axis was 63.2o and cells were randomly distributed. Cell alignment did not affect cell
proliferation. However, the highest ALP specific activity and the most homogeneous
mineral distribution were obtained on the Fb adsorbed micropatterned films.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/4/1082865/index.pdf |
| Date | 01 September 2003 |
| Creators | Kenar, Halime |
| Contributors | Hasirci, Vasif |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | Access forbidden |
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