Background: Colorectal cancer is the third most common cancer and cause of related deaths worldwide. Early colorectal cancer diagnosis is vital in reducing incidence and mortality. There is a need for the development of non-invasive screening tools for enhancing the detection of the disease. Cancer specific peptides are useful cancer targeting agents that can be used to specifically improve early detection strategies. Several cancer targeting peptides have been identified. Previous work investigated the specific binding of three of these peptides (p.C, p.L and p.14) conjugated to quantum dots and were found to bind to colorectal cancer cell lines (HT-29 and Caco-2). However, their uptake, localization and biodistribution in an in vitro and in vivo colorectal cancer model have not been determined. This is essential in gaining an understanding for future diagnostic or therapeutic based applications. Primary Aim: The aim of this study was investigate the localization of three selected peptides p.C, p.L and p.14 conjugated to gold nanoparticles in an in vitro and in vivo colorectal cancer model using HRTEM. Methodology: The AuNP/peptide conjugates were characterized by HRTEM and DLS. For in vitro studies; HT-29, Caco-2 and C3A cells were exposed to the AuNP-p.C, AuNP-p.L and AuNP-p.14, collected and processed for HRTEM to assess targeting and localization. For in vivo studies; the establishment of a colorectal cancer model using the AOM/DSS model 1 and 2 was conducted. Wistar rats were assigned to 6 groups, five experimental and 1 control group. Group 1 received AOM/DSS method 1 and was treated with AuNP-p.L. Group 2 and 3 received AOM/DSS method 2 and were treated with AuNP-p.C and AuNP-p.14. Group 4 and 5 remained healthy and treated with AuNP-p.C and AuNP-p.14. Group 6 remained healthy receiving no nanoparticle treatment. After treatment, rats were sacrificed and tissue was processed for HRTEM. Tissue chosen for HRTEM analysis included: Group 1 (inflamed colon, rectum, pancreatic and kidney), Group 4 (kidney) and Group 5 (liver). Results: results obtained from nanoparticle characterization suggested that nanoparticles were conjugated to their respective peptides and were stable in dispersion. For in vitro studies, results suggested no AuNP targeting and localization in HT-29 cell lines. For in vivo studies, no colorectal cancer tumours were induced. TEM micrographs did not indicate the presence of nanoparticles in colon, rectum, pancreatic, kidney and liver tissue. However, AuNPs were found in the kidney tissue (group 4). Conclusion: Although the overall objectives were not met, this study provided insight into TEM cell preparation and optimization for future nanoparticle cell interaction research. This study also demonstrated the absence of AuNPs in healthy tissue and the presence of AuNPs in healthy kidney tissue through renal clearance, a favourable quality for diagnostic or therapeutic applications.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:nmmu/vital:10351 |
| Creators | Cairncross, Lynn |
| Publisher | Nelson Mandela Metropolitan University, Faculty of Science |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis, Masters, MSc |
| Format | x, 74 leaves, pdf |
| Rights | Nelson Mandela Metropolitan University |
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