Electronic Theses and Dissertations

Identifier

489

Date

2011

Document Type

Thesis

Degree Name

Master of Science

Major

Biomedical Engineering

Committee Chair

Joel D Bumgardner

Committee Member

Warren O Haggard

Committee Member

Tomoko Fujiwara

Committee Member

Erno Lindner

Abstract

Nearly 60% to 67% of all injuries that occur annually within the US are due to musculoskeletal injuries, with over a million people requiring implants and bone grafting materials to reconstruct bone defects. Our lab has previously developed composite chitosan/nano-hydroxyapatite microsphere based bone grafts that had good compressive strengths, supported bone cell growth and mineralization in vitro, demonstrated biocompatibility and osteoconductivity in a rat calvarial defect model, and when loaded with rhBMP-2 was osteoinductive in a rat muscle pouch model. However, degradation of these scaffolds was very slow which may have limited the amount of new bone formed in vivo. The objectives of this research was to develop a novel composite Chitosan-PLGA microsphere based system prepared via a precipitation method with improved degradation and biological characteristics as compared to plain chitosan (CTS) microspheres. The effect of varying PLGA amounts within the CTS microspheres was evaluated via degradation and biocompatibility studies in addition to physiochemical properties. PLGA particles in the composite CTS-PLGA microspheres segregated to the surface of the microspheres resulting in roughened surface textures. In addition, composite microspheres also had reduced crystallinity resulting in reduced exothermic peak temperatures as seen from XRD and DSC studies; showed increased degradation and better osteoblast attachment as compared to plain CTS microspheres. However, no effect was seen on osteoblast proliferation over a 7 day cell culture period. The results of this study showed that composite CTS-PLGA microsphere based systems have the potential to be used in bone tissue engineering applications and future studies will be aimed at evaluating its potential as a dual drug delivery vehicle.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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