Development of an efficient test for autoimmune disease using gold nanoparticles

Publication Type:
Thesis
Issue Date:
2019
Full metadata record
Coeliac disease results because of an unusual immune response to the digestion of gliadin protein. Patients suffering from the disease show varying degrees of chronic inflammation within the small intestine ranging from mild lesions to completely flat mucosa. The immune response in turn, leads to the production of a number of cytokines and antibodies that are linked to the disease and its pathological effects. The released antibodies can be used as specific biomarkers for developing reliable diagnostic tests. Over the years, different approaches like the use of mucosal biopsy, genetic typing of the disease associated gene, gliadin induced cytokines, antibodies and auto-antibodies have been used to develop diagnostic tests for coeliac disease. However, in spite of the encouraging initial results in terms of sensitivity and specificity, the existing tests have limited scope as point-of-care tests. The current study was aimed at developing a coeliac diagnostic assay based on the properties of the gold nanoparticles combined with the specificity of the antibodies from serum as well as saliva. In this study, I developed a novel diagnostic test for coeliac disease based on the coating of gold nanoparticles with gliadin, the highly antigenic protein responsible for inducing the symptoms of coeliac disease. A novel protocol for binding the hydrophobic gliadin protein on the surface of the gold nanoparticles was developed in this study. This was followed by the development of a simple, single antibody serology based diagnostic test. Finally, I used the assay on thirty patient serum samples in a blinded assessment and compared the results with the data from previously run serological and pathological tests on these patients. When tested on real patient samples, the data showed that the developed assay had an overall accuracy of over 96%. Furthermore, I developed an assay based on the coating of gold nanoparticles with a peptide sequence derived from gliadin. To develop the serological assay based on the peptide functionalised nanoparticles, I first established a stable suspension of peptide coated gold nanoparticles and then tested the assay on spiked serum samples. I then used the assay to test thirty patient serum samples and found that the peptide functionalised nanoparticle-based assay could distinguish coeliac disease from non-coeliac disease patients with an accuracy of 86.6%. This study demonstrates the potential of gold nanoparticle-based approach to be adapted for developing a point-of-care screening assay for diagnosis for CD. The developed assay could be a part of an exclusion based diagnostic strategy and prove beneficial for testing high coeliac disease risk populations.
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