Dissertation
DOPED CALCIUM PHOSPHATE BASED BONE TISSUE ENGINEERING SCAFFOLDS AND PLASMA SPRAYED COATINGS FOR ORTHOPEDIC APPLICATIONS: ENHANCEMENT OF MECHANICAL AND BIOLOGICAL PROPERTIES
Doctor of Philosophy (PhD), Washington State University
01/2017
Handle:
https://hdl.handle.net/2376/117836
Abstract
The first objective of my research is to understand the effects of magnesium oxide (MgO), zinc oxide (ZnO), silicon oxide (SiO2), and silver oxide (Ag2O) on physical, mechanical, and biological properties of plasma sprayed HA coatings on titanium implants. Results showed that SiO2 and ZnO enhanced osteoblastogenesis and decreased osteoclastogenesis in vitro using an osteoblast and osteoclast coculture system. They also decreased bone resorption and expedited the bone remodeling process. The presence of MgO and SiO2 significantly increased the osteogenesis, osseointegration, and bone mineralization of HA coated titanium implants by the evaluation of their histomorphology in vivo using the rat femoral defect model. Implant pushout tests also showed a maximum shear modulus of 149.83 ± 3.69 MPa for MgO/SiO2-HA coated samples after 14 weeks of implantation, which was significantly higher than uncoated and HA coated samples. Thermal oxidation was used to make a less thermal conductive layer on titanium for increasing the crystallinity of plasma sprayed HA coating. In addition, the presence of MgO and SiO2 significantly enhanced osteoblast proliferation and differentiation of plasma sprayed HA coating. Laser engineered net shaping (LENSTM) was used to create a 3 wt. % HA coating on titanium before plasma sprayed HA coating, which increased the adhesive bond strength of plasma sprayed HA coating from 25.91 ± 2.27 MPa to 39.33 ± 4.17 MPa. In addition, with the addition of Ag2O and MgO, it should improve the antimicrobial and biological properties of plasma sprayed HA coating.
The second objective of my research is to investigate the effects of MgO and ZnO on physical, mechanical, and biological properties of TCP scaffolds prepared by sucrose template or 3D printing. The use of polycaprolactone (PCL) infiltration and microwave sintering enhanced the mechanical properties of TCP scaffolds using sucrose template. The presence of PCL and MgO/ZnO also showed enhanced osteoblast proliferation and differentiation. For 3D printed scaffolds, the presence of MgO and ZnO significantly improved the density, compressive strength, and osteogenic properties of porous 3D printed TCP scaffolds. In addition, the surface porous design enhanced the osteogenic property of porous 3D printed TCP scaffolds.
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Details
- Title
- DOPED CALCIUM PHOSPHATE BASED BONE TISSUE ENGINEERING SCAFFOLDS AND PLASMA SPRAYED COATINGS FOR ORTHOPEDIC APPLICATIONS: ENHANCEMENT OF MECHANICAL AND BIOLOGICAL PROPERTIES
- Creators
- Dongxu Ke
- Contributors
- Susmita Bose (Advisor)Amit Bandyopadhyay (Committee Member)Yuehe Lin (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Mechanical and Materials Engineering
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 240
- Identifiers
- 99900581515901842
- Language
- English
- Resource Type
- Dissertation