Doctoral Dissertations


Wei Xiao


"The purpose of this Ph.D. research was to address the clinical need for synthetic bioactive materials to heal defects in non-loaded and loaded bone. Hollow hydroxyapatite (HA) microspheres created in a previous study were evaluated as a carrier for controlled release of bone morphogenetic protein-2 (BMP2) in bone regeneration. New bone formation in rat calvarial defects implanted with BMP2-loaded microspheres (43%) was significantly higher than microspheres without BMP2 (17%) at 6 weeks postimplantation. Then hollow HA microspheres with a carbonate-substituted composition were prepared to improve their resorption rate. Hollow HA microspheres with ~12 wt. % of carbonate showed significantly higher new bone formation (73 ± 8%) and lower residual HA (7 ± 2%) than stoichiometric HA microspheres (59 ± 2% new bone formation; 21 ± 3% residual HA). The combination of carbonate-substituted hollow HA microspheres and clinically-safe doses of BMP2 could provide promising implants for healing non-loaded bone defects. Strong porous scaffolds of bioactive silicate (13-93) glass were designed with the aid of finite-element modeling, created by robocasting and evaluated for loaded bone repair. Scaffolds with a porosity gradient to mimic human cortical bone showed a compressive strength of 88 ± 20 MPa, a flexural strength of 34 ± 5 MPa and the ability to support bone infiltration in vivo. The addition of a biodegradable polylactic acid (PLA) layer to the external surface of these scaffolds increased their load-bearing capacity in four-point bending by ~50% and dramatically enhanced their work of fracture, resulting in a "ductile" mechanical response. These bioactive glass-PLA composites, combining bioactivity, high strength, high work of fracture and an internal architecture conducive to bone infiltration, could provide optimal implants for structural bone repair"--Abstract, page iv.


Rahaman, M. N., 1950-

Committee Member(s)

Brow, Richard K.
Day, D. E.
Asle Zaeem, Mohsen
Bal, B. Sonny


Materials Science and Engineering

Degree Name

Ph. D. in Materials Science and Engineering


National Institutes of Health (U.S.)


Supported by the National Institutes of Health (NIDCR), Grant #1R15DE023987-01


Missouri University of Science and Technology

Publication Date

Fall 2016

Journal article titles appearing in thesis/dissertation

  • Hollow hydroxyapatite microspheres: A novel bioactive and osteoconductive carrier for controlled release of bone morphogenetic protein-2 in bone regeneration
  • Preparation of resorbable carbonate-substituted hollow hydroxyapatite microspheres and their evaluation in osseous defects in vivo
  • Creation of bioactive glass (13-93) scaffolds for structural bone repair using a combined finite element modeling and rapid prototyping approach
  • Tough and strong porous bioactive glass-PLA composites for structural bone repair
  • Three-dimensional printing of silicon nitride with controllable shape and architecture by robocasting


xvi, 135 pages

Note about bibliography

Includes bibliographic references.


© 2016 Wei Xiao, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Subject Headings

Bone regeneration
Bioactive compounds
Glass in medicine
Tissue scaffolds

Thesis Number

T 11060

Electronic OCLC #