Date

2007

Author

Ndreu, Albana

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In this study a microbial polyester, poly(3-hydroxybutyrate-co-3- hydroxyvalerate) (PHBV), and its blends were wet or electrospun into fibrous scaffolds for tissue engineering. Wet spun fiber diameters were in the low micrometer range (10-50 μm). The polymer concentration and the stirring rate affected the properties the most. The optimum concentration was determined as 15% (w/v). Electrospun fiber diameters, however, were thinner. Solution viscosity, potential, distance between the syringe tip and the collector, and polymer type affected the morphology and the thickness of beads formed on the fibers. Concentration was highly influential; as it increased from 5% to 15% (w/v) fiber diameter increased from 284 ± 133 nm to 2200 ± 716 nm. Increase in potential (from 20 to 50 kV) did not lead to the expected decrease in fiber diameter. The blends of PHBV8 with lactide-based v polymers (PLLA, P(L,DL-LA) and PLGA (50:50)) led to fibers with less beads and more uniform thickness. In vitro studies using human osteosarcoma cells (SaOs-2) revealed that wet spun fibers were unsuitable because the cells did not spread on them while all the electrospun scaffolds promoted cell growth and penetration. The surface porosities for PHBV10, PHBV15, PHBV-PLLA, PHBV-PLGA (50:50) and PHBV-P(L,DL)LA were 38.0±3.8, 40.1±8.5, 53.8±4.2, 50.0±4.2 and 30.8±2.7%, respectively. Surface modification with oxygen plasma treatment slightly improved the cell proliferation rates. Consequently, all scaffolds prepared by electrospinning revealed a significant potential for use in bone tissue engineering applications; PHBV-PLLA blend appeared to yield the best results.

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http://etd.lib.metu.edu.tr/upload/12608226/index.pdf
https://hdl.handle.net/11511/16684

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Graduate School of Natural and Applied Sciences, Thesis