TitleThermodynamic design, characterization, and evaluation of a nanocrystalline hydroxyapatite collagen allograft composite
NameMossaad, Christina Marie (author), Riman, Richard (chair), Denhardt, David (internal member), Mann, Adrian (internal member), Anthony, Linda (internal member), Shimp, Lawrence (outside member), Rutgers University, Graduate School - New Brunswick,
SubjectMaterials Science and Engineering,
Transplantation of organs, tissues, etc.
DescriptionThere is a growing need for bone to be produced synthetically due to the rising rates of osteoporosis and decreasing levels of bone mineral density in the rapidly aging population of baby boomers. Bone is a complex composite material of hydroxyapatite and collagen built to withstand tremendous compressive and tensile loads. The inorganic phase can be synthesized by various techniques including sol-gel, phase transformation, hydrothermal, mechanochemical, chemical precipitation and precipitation in simulated body fluid. However, high temperatures, high pressures, extreme pH values, low yield, vigorous washing and long reaction times limit biological applications and processing with biological tissues such as allografts used in a manifold of medical applications. To address the gap in hydroxyapatite synthesis technology for these applications, the research was divided into three parts: thermodynamic modeling, powder characterization, and the application to allograft materials for in-vivo studies. The thermodynamic modeling contained in the first chapter investigated four precursor systems of interest and their fit or dissidence with the biomimetic paradigm proposed. The calcium acetate-potassium phosphate tribasic synthesis system was found to be the most robust and was thoroughly characterized in the second chapter, which revealed the particle size to be below 10 nm, which is among the smallest recorded in literature. In addition, characterization in this size range proved difficult and an uphill crystalline to amorphous phase transition was observed when left in dry storage over 5 months. In the third chapter, an inherent precursor buffering system was employed and the adaptation of the technology to aseptic conditions was carried out in effort to mineralize allograft materials for an in-vivo ectopic athymic rat study. The study revealed that the nanoscale hydroxyapatite synthesized on the surface allowed increased wet-state fiber cohesivity, which caused a change in tissue response over the control allograft where the allograft produced chondrocytes-cartilage-rich tissue and the composite produced osteoblast-adipose-rich tissue resembling bone marrow. Overall the research was successful in establishing the utility of thermodynamic modeling in designing a biomimetic system that can be aseptically adapted to allograft and other bone-related technologies, which is a rising field in the forefront of medicine.
NoteIncludes bibliographical references.
Noteby Christina Marie Mossaad
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
RightsThe author owns the copyright to this work.