Doctoral Dissertations

Author

Xin Liu

Abstract

"Biocompatible scaffolds that replicate the structure and function of bone would be ideal bone substitutes for structural bone loss, provided they have the requisite mechanical properties for reliable long-term loading. In this dissertation, strong porous scaffolds of silicate 13-93 bioactive glass, created with two different microstructures, were evaluated to determine their mechanical properties and their capacity to regenerate bone in a rat calvarial defect model. Scaffolds with an oriented microstructure of columnar pores were prepared by unidirectional freezing of camphene-based suspensions, followed by thermal annealing and sintering. By optimizing the freezing conditions, annealing time, and sintering temperature, constructs (porosity = 50 ± 4%; average pore diameter = 100 µm) were created with a compressive strength of 47 ± 5 MPa and an elastic modulus of 11 ± 3 GPa (in the orientation direction). New bone formation in the pore space of the scaffolds increased from 37% at 12 weeks to 55% at 24 weeks in vivo. Scaffolds with grid-like microstructure (porosity= 47 ± 1%; pore width = 300 µm), prepared by a robotic deposition (robocasting) technique, had a compressive strength (86 ± 9 MPa) and an elastic modulus (13 ± 2 GPa) comparable to human cortical bone, a Weibull modulus of 12, and excellent fatigue resistance in compression. Bone regeneration in the as-fabricated scaffolds in vivo (32% at 6 weeks) was significantly enhanced (to ~60%) by a surface treatment in an aqueous phosphate solution or loading the surface-treated scaffolds with bone morphogenetic protein-2 (1 µg/defect), prior to implantation. Scaffolds of 13-93 bioactive glass with a grid-like microstructure prepared by robocasting, showing better mechanical properties and a greater capacity to support bone formation, are more promising in structural bone repair "--Abstract, leaf iv.

Advisor(s)

Rahaman, M. N., 1950-

Committee Member(s)

Bal, B. Sonny
Brow, Richard K.
Brown, Roger F.
Day, D. E.

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Ceramic Engineering

Publisher

Missouri University of Science and Technology

Publication Date

2013

Journal article titles appearing in thesis/dissertation

  • Oriented bioactive glass (13-93) scaffolds with controllable pore size by unidirectional freezing of camphene-based suspensions: microstructure and mechanical response
  • Porous and strong bioactive glass (13-93) scaffolds prepared by unidirectional freezing of camphene-based suspensions
  • Bone regeneration in strong porous bioactive glass (13-93) scaffolds with an oriented microstructure implanted in rat calvarial defects
  • Mechanical properties of bioactive glass (13-93) scaffolds fabricated by robotic deposition for structural bone repair
  • Enhanced bone regeneration in rat calvarial defects implanted with surface-modified and BMP-loaded bioactive glass (13-93) scaffolds
  • Conversion of melt-derived microfibrous borate (13-93B3) and silicate (45S5) bioactive glass in a simulated body fluid

Pagination

xvi, 202 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2013 Xin Liu, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Library of Congress Subject Headings

Tissue scaffolds
Glass in medicine
Bioactive compounds
Bone regeneration

Thesis Number

T 10652

Print OCLC #

922574593

Electronic OCLC #

922574690

Link to Catalog Record

Electronic access to the full-text of this document is restricted to Missouri S&T users. Otherwise, request this publication directly from Missouri S&T Library or contact your local library.

http://laurel.lso.missouri.edu/record=b11034835~S5

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