Electronic Theses and Dissertations

Author

Hengjie Su

Date

2020

Date of Award

2020

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Committee Chair

Joel Bumgardner

Committee Member

Tomoko Fujiwara

Committee Member

Gary Bowlin

Committee Member

Jessica Jennings

Abstract

Guided bone regeneration (GBR) membranes are used for providing barrier function in guiding bone regeneration. Chitosan has been explored for making GBR membranes since it is biocompatible and biodegradable. Our group developed electrospun chitosan membranes (ESCM) using two novel post-spinning treatments; triethylamine (TEA)/di-tert-butyl dicarbonate (tBOC) treatment and the butyryl-anhydride (BA) treatment. These treatments prevented swelling and retained the nanofibrous structure of the membranes in aqueous environments, and exhibited physical properties, cell and tissue responses, and effective barrier function in vivo that are promising for GBR applications. The objectives of this research were to:1.Further evaluate impact of TEA/tBOC-stabilized nanofiber structure of electrospun membranes in fibroblast-osteoblast co-cultures.2.Evaluate TEA/tBOC treated chitosan electrospun guided bone regeneration membranes to augment bone healing in a grafted rodent calvarial defect model as compared to a commercial collagen membrane.3.Explore improving mechanical properties of the TEA/tBOC treated chitosan membrane using elastin.In the first objective, only the TEA/tBOC treated membranes exhibited the nanofibrous structure and the greatest pore volume as compared to traditional Na2CO3 treated ESCM or chitosan films. All these three types of membranes showed similar fibroblast and osteoblast proliferation capability. In a dual fibroblast-osteoblast cell culture, the TEA/tBOC treated ESCMs were more effective in promoting osteoblast mineralization. This result is significant in that it supports the hypothesis that the nanofibrous structure leads to effective nutrient exchange between the osteoblast and fibroblast growth environments leading to improved bone formation.In the second objective, rats with the chitosan membranes and the collagen membrane all showed significant increases in the bone growth after both 3 and 8 weeks. The chitosan membrane groups showed significant more bone density than the collagen membrane group, which might indicate that the chitosan membrane was more effective in promoting bone mineralization than the collagen membrane.In the third objective, chitosan added with elastin showed that the membrane with increased ratio of elastin has increased mechanical strength, fiber diameters and degradation ratio. In addition, all the chitosan-elastin membranes were compatible with fibroblasts and osteoblasts.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to ProQuest

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