SYNTHESIS AND CHARACTERIZATION OF POLYPHOSPHAZENES FOR SURFACE AND BIOMEDICAL APPLICATIONS
Open Access
- Author:
- Singh, Anurima
- Graduate Program:
- Chemistry
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- July 10, 2006
- Committee Members:
- Harry R Allcock, Committee Chair/Co-Chair
Alan James Benesi, Committee Member
John V Badding, Committee Member
Erwin A Vogler, Committee Member - Keywords:
- Biomaterial
Superhydrophobic
Polyphosphazenes
Biodegradable
Bone Tissue Engineering
Nanofibers - Abstract:
- The work presented in this thesis is based on the modification of surface and bulk properties of polyphosphazenes to form polymers with new and / or improved properties that are useful in advanced applications. Chapter 1 provides an introduction to this field and sketches the history and purpose of research in this area. Chapter 2 reviews the field of hydrophobic polyphosphazenes and their potential applications. Hydrophobic polyphosphazenes offer opportunities for the tuning of surface properties that are not found for many conventional hydrophobic materials. Chapter 3 describes a study involving surface modification of a hydrophobic, fluorinated polyphosphazene to form a superhydrophobic surface. The development of these superhydrophobic surfaces constitutes a significant advancement for fluorinated polyphosphazenes. It not only offers great potential as biomaterials and membranes for separation purposes but also widens the scope of applicability of these polymers in fields like self-cleaning surfaces and protective clothing applications. Chapter 4 discusses the development of biodegradable polyphosphazenes for bone tissue engineering application. This chapter reports on the design, synthesis, characterization and biological evaluation of L-alanine co-substituted polyphosphazenes. Chapter 5 deals with the processing of nanofiber and nanofiber composite scaffolds of poly[bis(ethyl alanato)phosphazene] by the process of electrospinning. Chapter 6 reports on the synthesis and characterization of tyrosine-functionalized polyphosphazenes. The physical and chemical properties of the polymers varied with the type of linkage between the tyrosine unit and phosphazene backbone. Properties such as bioerosion or pH sensitive behavior could be incorporated into one material by structural variations at the molecular level and are useful in applications such as tissue engineering and controlled drug delivery. Appendix a describes the development of low temperature setting polyphosphazene/ hydroxyapatite composites, potentially useful as bone tissue engineering materials. Appendix b reports on novel blends of hydrophobic, biodegradable polyphosphazene, poly[bis(ethyl alanato) phosphazene] and poly(lactic-co-glycolic)acid (LA: GA; 85:15), developed as candidates for bone tissue engineering applications. Blending of biodegradable polyphosphazenes with PLAGA was attempted in order to combine the beneficial features of PLAGA such as recognized biocompatibility and widespread applicability with the osteoconductivity, well tuned degradability as well as the buffering capacity of the degradation products of polyphosphazenes.