Desenvolvimento de biossensor eletroquímico utilizando ácido 4-hidroxibenzóico para detecção do biomarcador GSTM3 visando diagnóstico precoce de câncer de próstata

Abstract

Prostate cancer is the second most common type of carcinoma among men, often diagnosed late due to its asymptomatic progression. Currently, the healthcare system offers invasive and time-consuming detection techniques such as the digital rectal exam and prostate-specific antigen testing, methodologies that present limitations like false positives caused by other benign conditions. Therefore, it is necessary to develop new methodologies to obtain a rapid and minimally invasive method for discriminatory diagnosis of the disease. The research aimed to develop a pencil graphite electrode polymerized with 4-hydroxybenzoic acid to immobilize anti-GSTM3 for detecting the prostate cancer biomarker GSTM3. The study was conducted in an electrochemical cell connected to a potentiostat, having Ag/AgCl as reference electrode and a platinum counter electrode. Working electrodes were modified through polymerization of the 4-hydroxybenzoic acid monomer via cyclic voltammetry, with subsequent evaluation by electrochemical impedance spectroscopy. Afterwards, immobilization of the anti-GSTM3 antibody was performed followed by detection in clinical serum samples containing GSTM3. Finally, biosensor parameters were optimized and the dilution limit was determined. The modification of the pencil graphite electrodes was successful, allowing the antibody to be immobilized on the polymer through covalent bonding, showing that the matrix is efficient in constructing this type of biosensor. In clinical samples, the system proved efficient for antigen detection, having a dilution limit of 1:1280. Thus, the modified pencil graphite electrode proves effective in forming interactions with antibody molecules, constituting an efficient platform for detection of the GSTM3 biomarker.