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Nanomedicines for the treatment of coagulation disorders
Maguire, Ciar?n Manus
THESIS 10966 Nanomaterials are becoming increasingly utilised in all areas of science, technology and healthcare. More specifically in terms of nanomedicine, the physical and chemical properties of the materials allow for application in diagnostics, therapeutics, drug delivery and multifunctional theranostic agents. Prior to any potential clinical application, nanomaterials intended for use in vivo must be compressively examined for toxicity and other bio-incompatibility issues. Following introduction into the human body one can expect a critical interaction will take place between the nanoparticle and the blood components, most notably with the constituents of the coagulation cascade. One of fundamental challenges in the area of application development is related to generating reliable and reproducible characterisation data for nanomaterials. Characterisation is critical, not only for understanding the mechanism of action of nanotherapeutics, but also to comply with directives, procedures and regulation requested by regulatory agencies. As such, in this presented research, we set out to develop robust, reliable and accurate characterisation protocols for the analysis of nanoparticles in liquid suspension using Nanoparticle Tracking Analysis (NTA) developed by NanoSight Malvern Ltd. Through the implementation of multiple rounds of interlaboratory comparison (ILC) with 12 pan-national institutions, the percentage coefficients of variation for monodisperse and complex mixtures of nanoparticles were dramatically reduced across the board. The characterisation of nanoparticles in complex dispersal media was also examined. This led to the refinement of standard operating procedures not only for sample characterisation, but also sample shipping, handling and preparation. Software advancements also improved the resolution of size distribution graphs and were instrumental in the analysis of multimodal samples. The refinement of the NTA technique was critical in the analysis of multiple sample types presented in this thesis. Throughout the course of this study, various nano-objects were characterised, including gold nanoboxes and bismuth ferrite nanoparticles, as well as more biologically and clinically relevant samples including exosomes and virus particles. NTA was utilised to study the stability of particles in cell culture medium, as well as the impact of storage and isolation method on exosome size. It was demonstrated that nanomaterial size and material type are important factors when studying the interaction of nanoparticles with cell lines. Similarly, NTA was used to assess the impact on size and concentration of Adenovirus particles following incremental heating and exposure to gold nanoparticles. Here it was illustrated that exposure to gold nanoparticles increase the temperature at which the virus capsid ruptures. NTA was also utilised in the characterisation of functionalised iron oxide nanoparticles for applications in the treatment of coagulation disorders. Here, a selection of particles were screened for their effect on the coagulation cascade and the most appropriate candidate was then selected to be functionalised with the anticoagulant heparin. The nanoparticles were functionalised using numerous approaches and then characterised by NTA. Following characterisation, the functionalised materials were tested for their anticoagulant activity. It was demonstrated that upon conjugation of heparin to the nanoparticle, heparin loses its anticoagulant properties, most likely due to its inability to bind its targets antithrombin and thrombin. Finally, cadmium telluride quantum dots (QDs) were investigated for their effect on the coagulation cascade. It was demonstrated that 3.2 nm QDs illicit a strong anticoagulant response on the intrinsic coagulation pathway. No anticoagulant response was observed for their relatively larger 3.6 nm counterparts. It was reported that the activity of the intrinsic coagulation factors were within their normal respective ranges. The greatest reduction in activity was observed for Factor VIII, with an activity of 51 % of normal. This reduction in activity would not typically cause the massive prolongation of the clotting times observed in this thesis, but the effect may be additive to alterations in function of other coagulation proteases and cofactors. It was also demonstrated that increases in calcium concentration result in a corresponding increase in clotting times suggesting that the 3.2 nm QDs interact with the calcium ions required for normal haemostasis. In conclusion, this thesis demonstrates that the development of robust procedures for the characterisation of nanoparticles by NTA reduces the user-to-user variation and increases the reproducibility of the analysis. Further, it was shown that when heparin is conjugated onto the surface of nanoparticles, a corresponding loss in the anticoagulant properties of the drug is observed. Finally, it was illustrated that cad...
Keyword(s): Clinical Medicine, Ph.D.; Ph.D. Trinity College Dublin
Publication Date:
2016
Type: Doctoral thesis
Peer-Reviewed: Unknown
Language(s): English
Institution: Trinity College Dublin
Citation(s): Ciar?n Manus Maguire, 'Nanomedicines for the treatment of coagulation disorders', [thesis], Trinity College (Dublin, Ireland). School of Medicine. Discipline of Clinical Medicine, 2016, pp.223
Publisher(s): Trinity College (Dublin, Ireland). School of Medicine. Discipline of Clinical Medicine
Supervisor(s): Prina-Mello, Adriele
Volkov, Yuri
O'Donnell, James
First Indexed: 2018-06-28 06:11:16 Last Updated: 2018-08-24 06:41:15