Date of Award

2016

Document Type

Doctoral Thesis

Degree Name

Doctor of Philosophy

Department

Biological Sciences

First Advisor

Dr. Helen O'Shea

Second Advisor

Dr. Daniel Boyd

Third Advisor

Dr. Hugh McGlynn

Abstract

Within the biomaterial community significant effort has been directed towards engineering materials that induce precise host responses, which are tailored to specific applications. However, this has also seen an increase in the complexity of some biomaterials, which is being increasingly criticised within the literature, as it is attributed to hindering their clinical utility. In this context the release of therapeutic metal ions from glass-based biomaterials have been shown to promote hard tissue repair and regeneration through angiogenesis and osteogenesis processes. Within this thesis project two separate quaternary high borate glass systems were prepared containing the therapeutic metal ions strontium and gallium.

Within study one and two the composition-structure-property relationships of each glass system was evaluated based on the increasing substitution of La203 or Ga203 for Na20. The ion release capabilities were evaluated after extraction at 37 °C in a shaking water bath (2Hz, longitudinal movement). Increasing substitutions of La203:Na20 did not appear to dramatically alter the structure of the glass, specifically boron speciation, however the hydrolytic stability of the glasses was increased, which in turn significantly affected ion release. The increasing substitutions of Ga203:Na20 had a profound effect on the glass structure and boron speciation; linear increases in the relative concentration of hydrolysable BO3 units and linear decreases in the relative concentration of more hydrolytically stable BO4 structural units was observed. Irrespective of this, at >= 6:4 Ga203:Na20 ratio, network stabilization appeared to occur, with decreases in ion release observed.

Within study three (sub-chronic pilot study) a rabbit long-bone model was utilized to explore the safety and efficacy of LB 102 (i.e. from the strontium release lanthanum containing high-borate glass series) for bone regeneration. Histopathological examination revealed that LB 102 demonstrated osteoconductive and osseointegrative properties with greater new bone being formed within and surrounding LB 102 particles, when compared to the untreated control.

These studies demonstrated the possible utility of high borate glasses to act as controllable degradable materials for the delivery of therapeutic metal ions, strontium and gallium.

Access Level

info:eu-repo/semantics/openAccess

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