Jiang, Yu;
(2021)
Development and characterization of co-substituted hydroxyapatites for biomedical applications via advanced electrohydrodynamic processing.
Doctoral thesis (Ph.D), UCL (University College London).
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Yu Jiang PhD Thesis student ID number 15042196.pdf Download (32MB) | Preview |
Abstract
Hydroxyapatite (HA) is a well-known bioactive material for biomedical applications, particularly for bone graft and implant coatings. Substitutions with metal ions in HA can provide add-on functions, such as magnetic property by adding Fe3+ and Mn2+ and antimicrobial property by adding Cu2+ and Zn2+. Electrohydrodynamic atomization (EHDA) has been developed for coating using nanosuspensions. The stability of Taylor cone in EHD jetting was improved by a modification of nozzle geometry. Spherical-nozzles introduced were able to overcome the instability caused by frequent spray-mode switches, which interferes coating processing. As a result, the uniformity of the deposition was improved and 10-fold increase in the through-put of processing of HA nanosuspensions was achieved. Importantly, a stable cone-jet could be achieved with a water-ethanol ratio up to 4:1, which was significantly improved from 5% aqueous solution with conventional nozzle and extended the range of processable materials. Iron and manganese co-substituted HA (Fe-MnHA) has been synthesized to combine magnetic property with bioactivity. An analysis of the deposition of nanoparticles (NPs) using template-assisted electrohydrodynamic atomization (TAEA) under magnetic field showed that Fe-MnHA NPs was highly responsive in comparison with mono-substituted HAs, magnetic iron oxide nanoparticles (IONPs) and IONPs-HA mixture (50/50wt%). The in vitro bioactivity of Fe-MnHA was in the same level as HA but higher than IONPs and their mixture in simulated body fluid (SBF) testing. Therefore, Fe-MnHA balanced the magnetic property and bioactivity, and may have a great potential in biomedical applications, from cell guidance, contrast agents for medical imaging to cancer therapy. Multifunctional copper and zinc co-substituted HA (Cu-ZnHA) has been formulated to combine bioactivity with antimicrobial ability. Flow cytometry and crystal violet assays indicated its effective antibacterial and antibiofilm ability against E. coli and S. aureus. At the lowest metallic content (0.005mol%), Cu-ZnHA was not only antibacterial, but also showed a high biocompatibility by supporting the growth of human osteoblast-like MG63 cells. Therefore, Cu-ZnHA is a promising material for developing multifunctional implant coatings.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Development and characterization of co-substituted hydroxyapatites for biomedical applications via advanced electrohydrodynamic processing |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2021. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10134934 |
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