Biossensor eletroquímico para detecção de vesículas extracelulares pequenas provenientes de câncer de mama

Abstract

Cancer is a group of diseases characterized by the disordered proliferation of cells, which can invade other organs and tissues. Breast cancer (BC) is the most common disease in women worldwide, with more than 2 million cases and 685,000 deaths from the disease in 2020. Diagnosis at an early stage of the disease is a crucial factor to increase the chances of breast cancer patient survival. Currently, diagnosis is performed by mammography and tissue biopsy. However, these methods require laboratory infrastructure and specialized human resources, making the process expensive and time-consuming. For this reason, new biomarkers are being investigated for the diagnosis of the disease, such as the Del-1 protein present in small extracellular vesicles (SEVs) from breast tumor cells. In this project, a system for the detection of SEVs is proposed for the diagnosis of breast cancer. Gold electrodes were modified with antibodies against the CD63 protein, present in general SEVs, to capture them. A second step consists of functionalizing gold nanoparticles (AuNps) with anti-Del1 antibodies, used for labeling SEVs from cancer cells. The steps were monitored by electrochemical impedance technique. Breast and lung cancer cells were cultured; their SEVs were extracted by ultracentrifugation and quantified by NTA. It was aimed to obtain a system capable of detecting CM in a non-invasive and point-of-care way through a sensitive, fast, and low-cost immunosensor. However, none of the different strategies used was able to detect the SEVs. This work contributes to a new questioning about the cellular location of the Del-1 biomarker and points out analyzes that are still necessary for this protein to be explored for the diagnosis of breast cancer.