ETD

• antibodies
• circulating tumour cells
• immunosensor
• nanomaterials

Early detection of circulating tumour cells (CTCs) plays a crucial role in the clinical management of melanoma, as the spread of metastasis originating from CTCs represents the leading cause of mortality among oncologic patients. However, their extremely low concentration in peripheral blood (1-100 cells/mL) makes their detection particularly challenging, requiring highly sensitive and selective analytical tools. Conventional diagnostic methods are often expensive, rely on subjective evaluation of cell morphology, and, above all, show limited effectiveness in detecting melanoma CTCs.
The work of this thesis is part of the COMET project, which aims to create a lab-on-a-chip (LOC) platform capable of isolating and counting CTCs from whole blood samples. Specifically, this work focuses on the development of the immunosensor integrated into the platform.
The immunosensor is based on a gold screen-printed electrode, modified with two-dimensional nanomaterials, which increase the electroactive surface area, thereby improving the signal-to-noise ratio. These nanomaterials, functionalized with aminosilanes, enable the stable immobilisation of monoclonal antibodies specific for the MCAM antigens expressed on melanoma CTCs. Electrochemical impedance spectroscopy (EIS) was employed as the signal transduction technique, as it allows monitoring of variations in charge transfer resistance (Rct) following antigen–antibody binding events.
Sensor performance was optimised by investigating key parameters, including antibody incubation time, concentration and temperature; cell incubation time; and by implementing blocking strategies to minimise non-specific cell adsorption. Preliminary experimental results demonstrate the proper functioning of the immunosensor and confirm its ability to selectively distinguish melanoma CTCs from other cell types.
Overall, the developed system represents a fundamental step toward the integration of the immunosensor into the LOC platform. It shows strong potential for the development of rapid and minimally invasive diagnostic tools, with the possibility of extending the approach to other tumour types through the selection of appropriate antibody markers.