Design and Optimization of Angiogenic, Antibacterial Si-Zn-Hydroxyapatite for Use as Filler Particles in Polycaprolactone Nanocomposites
type: CreativeWork
description: The development of synthetic biomaterials that replicate the biological functionality and mechanical resilience of native bone remains a central challenge in tissue engineering. Hydroxyapatite (HAp) is a widely used osteoconductive ceramic, but clinical outcomes can be limited by relatively low levels of bioactivity, inherent brittleness, slow in vivo resorption, and susceptibility to post-operative infection. This thesis establishes a mechanistically informed framework for engineering multifunctional bone-regenerative materials by controlling properties from atomic-scale structure and chemistry to macroscopic behaviour. Phase-pure, thermally stable ion-doped HAp was synthesized via aqueous precipitation. Co-doping with silicon and zinc (Si-Zn-HAp) was optimized through control of stoichiometry and processing conditions, and this work extended the previously reported Zn solubility limit in HAp, enabling the formation of continuous solid solutions containing up to 1.35 wt% Si and 0.96 wt% Zn without secondary phase formation. Comprehensive characterization using Rietveld refinement and spectroscopic analyses confirmed that Si and Zn substitutions induce distinct, predictable changes in lattice parameters and microstructure, providing a platform for subsequent biological investigation. In vitro co-cultures of human osteoblasts (hOBs) and human dermal microvascular endothelial cells (hDMECs) on dense Si-Zn-HAp surfaces revealed that osteogenic and angiogenic activity are governed primarily by surface properties rather than direct ionic stimulation. Si substitution resulted in the refinement of the surface grain structure and significantly enhanced hOB proliferation, as well as the self-assembly of endothelial cells into vessel-like structures. Notably, co-doping with Si neutralized an otherwise inhibitory effect of Zn on vasculogenesis, yielding a synergistic enhancement of both osteogenic and angiogenic potential in the Si-Zn-HAp system. The prevailing hypothesis for …
abstract: The development of synthetic biomaterials that replicate the biological functionality and mechanical resilience of native bone remains a central challenge in tissue engineering. Hydroxyapatite (HAp) is a widely used osteoconductive ceramic, but clinical outcomes can be limited by relatively low levels of bioactivity, inherent brittleness, slow in vivo resorption, and susceptibility to post-operative infection. This thesis establishes a mechanistically informed framework for engineering multifunctional bone-regenerative materials by controlling properties from atomic-scale structure and chemistry to macroscopic behaviour. Phase-pure, thermally stable ion-doped HAp was synthesized via aqueous precipitation. Co-doping with silicon and zinc (Si-Zn-HAp) was optimized through control of stoichiometry and processing conditions, and this work extended the previously reported Zn solubility limit in HAp, enabling the formation of continuous solid solutions containing up to 1.35 wt% Si and 0.96 wt% Zn without secondary phase formation. Comprehensive characterization using Rietveld refinement and spectroscopic analyses confirmed that Si and Zn substitutions induce distinct, predictable changes in lattice parameters and microstructure, providing a platform for subsequent biological investigation. In vitro co-cultures of human osteoblasts (hOBs) and human dermal microvascular endothelial cells (hDMECs) on dense Si-Zn-HAp surfaces revealed that osteogenic and angiogenic activity are governed primarily by surface properties rather than direct ionic stimulation. Si substitution resulted in the refinement of the surface grain structure and significantly enhanced hOB proliferation, as well as the self-assembly of endothelial cells into vessel-like structures. Notably, co-doping with Si neutralized an otherwise inhibitory effect of Zn on vasculogenesis, yielding a synergistic enhancement of both osteogenic and angiogenic potential in the Si-Zn-HAp system. The prevailing hypothesis for …
author: Kreuz, Tim
language: eng
keywords: Biomaterials, Hydroxyapatite, Ion-Doping, Composites, Materials Science
license: https://www.repository.cam.ac.uk/bitstreams/aa671764-b378-42a7-9eef-02fcbd185d9b/download
license: http://purl.org/NET/rdflicense/allrightsreserved
date published: 2025-07-30
date modified: 2026-07-22T22:23:56Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.124087