Electronic Theses and Dissertations

Identifier

484

Date

2011

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Biomedical Engineering

Committee Chair

Joel D Bumgardner

Committee Member

Warren O Haggard

Committee Member

Eugene C Eckstein

Abstract

Guided tissue regeneration (GTR) is a surgical technique commonly used to exclude bacteria and soft tissues from bone graft sites in oral/maxillofacial bone graft sites by using a barrier membrane to maintain the graft contour and space. Current clinical barrier membrane materials based on expanded polytetrafluoroethylene (ePTFE) and bovine type 1 collagen are non-ideal and experience a number of disadvantages including membrane exposure, bacterial colonization/biofilm formation and premature degradation, all of which result in increased surgical intervention and poor bone regeneration. These materials do not actively participate in tissue regeneration, however bioactive materials, such as chitosan, may provide advantages such as the ability to stimulate wound healing and de novo bone formation. Our hypothesis is that electrospun chitosan GTR membranes will support cell attachment and growth but prevent cell infiltration/penetration of membrane, demonstrate in vitro degradation predictive of 4-6 month in vivo functionality, and will deliver antibiotics locally to prevent/inhibit periopathogenic complications. To test this hypothesis a series of chitosan membranes were electrospun, in the presence or absence of genipin, a natural crosslinking agent, at concentrations of 5 and 10 mM. These membranes were characterized by scanning electron microscopy, tensile testing, suture pullout testing, Fourier transform infrared spectroscopy, X-ray diffraction, and gel permeation chromatography, and in vitro biodegradation for diameter/morphology of fibers, membrane strengths, degree of crosslinking, crystallinity, molecular weight, and degradation kinetics, respectively. Cytocompability of membranes was evaluated in osteoblastic, fibroblastic and monocyte cultures. The activity of minocycline loaded and released from the membranes was determined in zone of inhibition tests using P. gingivalis microbe. The results demonstrated that genipin crosslinking extended the in vitro degradation timeframe, extended the release of minocycline, and increased the tensile strength of the resultant membranes while cytocompatibility, swelling, and tear strength were unaffected. In conclusion, electrospun chitosan membranes crosslinked with genipin are a suitable material for guided tissue regeneration and may help reduce bacterial infection and bacteria-induced host inflammatory response.

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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