In the present thesis we propose the development of hybrid polymer titanium dioxide (TiO2) nanoparticles for use in biomedical applications. TiO2 exhibits high biocompatibility in the dark however, upon illumination in aqueous media with near UV light it produces an array of reactive oxygen species (ROS) which have the capability to induce death in neighbouring cells. The process of inducing cell death using a photosensitive material which produces ROS is known as photodynamic therapy (PDT) and is used to treat a wide range of maladies from psoriasis to cancer.We have demonstrated the ability to produce anatase nanoparticles with high control over their resulting size through a novel water mediated sol-gel synthetic method in benzyl alcohol, using either Ti(OnPr)4, Ti(OnBu)4 or Ti(OiPr)4 as the metal precursor. Through dynamic light scattering (DLS) analysis we have shown that the mechanism of nanoparticle growth appears to proceed through the agglomeration of primary nanoparticles formed instantly upon adding the reagents together. After synthesis the nanoparticles could be easily redispersed in aqueous media at pH2 with any further agglomeration being controlled by the parent alkoxide.After synthesis the nanoparticles were coated with PEG, conjugated to either a catechol or phosphate as ligand, in order to stabilise the nanoparticles at neutral pH. Uncoated nanoparticles exhibited good photoactive capability in the photooxidation of methylene blue. However, on coating with catechols the photoactivity of the nanoparticles was abolished. Coating with phosph(on)ates on the other hand preserved or even enhanced the photoactivity which makes this system promising for in vivo applications.At the same time this thesis also reports preliminary investigations on the use of TiO2 embedded into the walls of model drug loaded poly electrolyte multilayer microspheres for UV triggered delivery applications.
|Date of Award||1 Aug 2013|
- The University of Manchester
|Supervisor||Francesco Cellesi (Supervisor) & Nicola Tirelli (Supervisor)|
- Poly electrolyte multiwalled microspheres
- Sol-gel synthesis
- Photodynamic therapy
- Titanium dioxide nanoparticles