Abstract
Most oral cancers are oral squamous cell carcinomas (OSCC) that arise from the epithelial lining of the oral mucosa. Given that the oral cavity is easily accessible, the disease lends itself to early detection; however most oral cancers are diagnosed at a late stage and approximately half of oral cancer sufferers do not survive beyond 5 years, post-diagnosis. The low survival rate has been attributed to late detection but there is no accepted, reliable and convenient method for the detection of oral cancer and oral pre-cancer. Dielectrophoresis (DEP) is a label-free technique which can be used to obtain multi-parametric measurements of cell dielectric properties. Parameters, such as cytoplasmic conductivity and effective membrane capacitance (CEFF), can be non-invasively determined by the technique. This thesis presents a study of the application of DEP in the detection of oral cancer. A novel DEP-microwell electrode system, developed at the University of Surrey, has been used to investigate the dielectric properties of normal, pre-malignant and malignant oral epithelial cells. In this study, significant differences in the dielectric properties of normal, pre-malignant and malignant oral cells grown in standard 2-dimensional monolayer and reconstituted 3-dimensional organotypical cultures were observed. In addition, variations in the dielectric properties of oral cells were observed between culture conditions. To determine the sensitivity of DEP to detect a subpopulation of cancer cells in a host population of normal cells, the dielectric properties of host normal oral epithelial cells spiked with subpopulations of malignant oral epithelial cells, grown in reconstituted organotypical models, have been studied. In addition, the dielectric properties of exfoliated oral cells harvested by non-invasive brush biopsy from healthy subjects, clinically healthy tissue in patients with pre-malignant or malignant oral epithelial disease, pre-malignant oral patient tissue and malignant oral patient tissue were characterised. The results show that the dielectric properties of exfoliated oral cells from malignant oral tissue are different to the dielectric properties of cells harvested from healthy oral tissue.