Dissertation
Directing biomimetic morphology and mineralization of nanofiber shish-kebabs
Doctor of Philosophy (Ph.D.), Drexel University
Sep 2020
DOI:
https://doi.org/10.17918/00000168
Abstract
Human bone has an innate ability to heal itself, except in cases of large-scale injury to the bone tissue. In order to facilitate bone healing after substantial damage, synthetic bone grafts are promising options for temporarily replicating the function of bone while encouraging new tissue to form. To be an effective bone substitute, materials should be able to mimic bone's robust mechanical and biological properties originating from its nanoscale composite structure. By understanding more about how bone forms, new materials can be developed that not only have enhanced orthopedic healing capacity, but can function as mechanically robust composites. In this dissertation, polymeric hierarchical nanostructures called nanofiber shish-kebabs (NFSKs) are evaluated for their potential to recruit and control the development of a calcium phosphate mineral phase. The morphology of the shish-kebab nanostructures is shown to be controlled through electrospinning parameters and controlled crystallization conditions. A variety of NFSKs are formed with homopolymer or multi-polymer compositions in order to increase the chemical versatility and functionality of the fibrous polymer structures. Although much research has been conducted on designing bio-inspired artificial bone, the role that biological macromolecules play in influencing the formation of biominerals is not fully understood. To study this, materials were designed containing charged functional groups, with the goal of gaining insight into how these synthetic polymers can guide bio-mimetic composite formation. Poly (acrylic acid) (PAA) was selected as an anionic polymer which can recruit calcium cations from an ion-rich mineralization solution. Bio-mimicking synthetic scaffolds were fabricated with a variety of PAA architectures to study its effect on mineral formation. PAA within kebab crystals has the effect of promoting mineral formation within the PAA domains of the scaffold, forming a bone-mimicking, rapidly-forming composite material. This is found to contrast with PAA homopolymer chains in the mineralization solution, which have an inhibitory effect on mineral nucleation and growth. PAA can be used to carefully design the location and formation of materials, and an increased understanding of this process can lead to composites with precisely controlled nanostructures and properties.
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Details
- Title
- Directing biomimetic morphology and mineralization of nanofiber shish-kebabs
- Creators
- Sarah Emily Gleeson
- Contributors
- Christopher Y. Li (Advisor)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- 253 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Materials (Science and) Engineering (Metallurgical Engineering) (1970-2026); College of Engineering (1970-2026); Drexel University
- Other Identifier
- 991014695247504721