Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Master of Science

Program

Chemistry

Supervisor

Liu, Lijia

Abstract

The study and commercialization of calcium phosphate (Ca-P) coatings has occurred for several decades. However, this has typically involved the use of hydroxyapatite. This thesis presents the synthesis of different Ca-P-based coatings that has not been studied. Anodic oxidation was employed to create a porous Ti substrate, while pulsed electrochemical deposition was used to deposit the coating onto the Ti. The first coating synthesized was a calcium phosphoserine (Ca-pSer) complex, which contained two different morphologies: a flower-like structure at low deposition time and a unique cubic morphology at higher deposition times. Next, an amorphous calcium phosphate coating was synthesized and stabilized using ATP. A biocompatibility test revealed that the ACP coating had high cell proliferation. Lastly, differing concentrations of zinc was introduced to the Ca-pSer system. Microspheres were formed at 5 mol% Zn, whereas using 10 mol% Zn, it is suspected that Zn replaces Ca in the Ca-pSer complex.

Summary for Lay Audience

Currently in modern biomaterial research, there is much interest surrounding the use of titanium (Ti) and Ti-based materials as metallic implants for orthopedic and dental applications. Ti has proven to be an excellent candidate to fulfill this role as it is non-toxic and contains desirable mechanical properties, allowing it to support the weight of the human body in a safe manner. Despite these properties, osseointegration has proven to be a challenge due to the metallic nature of Ti. Due to what’s known as the foreign body response, the immune system may reject the implant, causing it to become encapsulated by unwanted fibrous tissue. To overcome this obstacle, the substrate surface must be modified. Specifically, by depositing a thin layer of calcium phosphate (Ca-P) onto the substrate surface, not only would the immune system recognize this foreign material, but it would also improve the chemical bonding between the implant and bone.

As the global population continues to increase, so does the need for metallic implants to support, replace and enhance pre-existing biological structures. However, the deposition of Ca-P (hydroxyapatite) onto implant surfaces has already been studied extensively and has even been commercialized for several decades. In this thesis, an electrochemical method was employed to synthesize different Ca-P coatings, using non-traditional chemical precursors. The aim of this project is to explore the use of various Ca-Ps in the form of a bioactive coating which may lead to improved biological advantages and unique biomedical applications.

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