Development of electrochemical biosensors for early diagnosis of breast cancer

Abstract

Breast cancer is the second most common type of cancer in women. In 2018, 2,1 million of new cases were reported worldwide, being 59.700 occurred in Brazil. Early diagnosis of the disease is a crucial factor to increase patient's chances of survival. Currently, breast cancer diagnosis is performed by mammography and tissue biopsy. However, these methods require costly equipment and specialized professionals, contributing to an expensive and late diagnosis. To speed up diagnosis results, new biomarkers have been investigated to be used as cancer breast diagnosis, such as Del-1 protein (Developmental endothelial locus-1) which is found in exosomes from breast tumor cells. This project proposes the development of an exosome detection system for breast cancer diagnosis. Gold electrodes will be modified with antibodies against CD63 proteins, found in general exosomes. Gold nanoparticles functionalized with antibodies against Del-1 will be used to label breast cancer exosomes. These steps will be monitored by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Gold nanoparticles will be synthesized by citrate reduction method and characterized by dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), Zeta potential and UV-Vis spectroscopy. To perform specificity tests, breast, liver and lung cancer cells will be cultured; their exosomes will be extracted by ultracentrifugation and quantified by DLS and NTA. We expected to obtain promising results for early, non-invasive and point-of-care breast cancer detection through a sensitive, fast and low cost immunosensor.