The synthesis, characterisation and bioapplications of Novel Gold-Zinc Telluride Core-shell Nanoparticles
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Date
2016
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University of Zululand
Abstract
There is a growing demand for the development of innovative nano-drug delivery
systems that can both target and improve cancer therapies more effectively than
conventional chemotherapy. Novel Au-ZnTe nanoparticles was designed to support
biocompatibility features that can be utilised for drug delivery and bio-imaging
applications. Au, ZnTe and Au-ZnTe nanoparticles were synthesized and analysed for optical, morphological, crystalline and surface chemistry characterisation. Subsequent to materials characterisation, Au-ZnTe nanoparticles was evaluated for its potential toxicity using in vitro and in vivo systems. The nanoparticle was surface modified through conjugation with 5-FU and human epidermal growth factor antibody to facilitate targeted anti-cancer drug delivery, followed by the in vitro drug efficacy
application. The Au-ZnTe nanoparticles displayed core-shell morphology with an
average particle size of 7 ± 3.74 nm. The absorption wavelength of Au-ZnTe
nanoparticles was dominated by the optical properties of gold and photoluminescence analysis showed that ZnTe dominated the emission properties of Au-ZnTe nanoparticles. Crystalline analysis displayed peaks attributed to both parental materials. The biosafety and cytotoxicity of these nanoparticles was established using normal human colon, mammary epithelial and cancer cells of breast, prostate and colon origin. Moreover, under certain conditions the particles expressed cytokines in low concentrations and induced an insignificant (20%) cytotoxic response when exposed to human peripheral blood mononuclear cells. Additionally systemic circulation of Au-ZnTe particles displayed no adverse effects in the blood, liver and kidney functions of female Sprague Dawley rats. TEM, FTIR, Zeta potential and optical measurements were performed to confirm the surface conjugation and interaction of 5-FU and EGF to Au-ZnTe nanoparticles. The in vitro anti-cancer therapeutic efficacy study was performed using the MTT cytotoxicity assay on breast cancer cells. The cytotoxicity studies have shown that all components in the 5-FU-EGF-Au-ZnTe nanoparticle formulation work synergistically to attack MCF7 cancer cells displaying 24.74 % increased efficacy than 5-FU at equivalent concentrations. Furthermore receptorligand mediated uptake of nano-drug formulations was demonstrated using 5-FU-Au-ZnTe. Several attempts were made to induce and develop a tumour model using Sprague Dawley rats and BALB/c mice. The presence of an external tumour mass was unsuccessful and therefore limited the ability to demonstrate the in vivo therapeutic efficacy of 5-FU-EGf-Au-ZnTe nanoparticles. These findings however lay a foundation for future work involving the synthesis and application of biocompatible nanoparticles that can support and improve current medical technologies. This study has generated valuable new knowledge that will help scientists within the field of biotechnology, nanomedicine, biochemistry and materials chemistry, to develop and optimize strategies for more efficient therapeutic application of nanomaterials.
Description
A dissertation submitted to the Faculty of Science and Agriculture in fulfillment of the requirements for the Degree of Doctor of Philosophy in the Department of Biochemistry and Microbiology at the University Of Zululand, 2016
Keywords
nano-drug delivery systems --Novel Au-ZnTe --nanoparticles