SCREEN-PRINTED ELECTROCHEMICAL IMMUNOSENSOR MODIFIED WITH GOLD NANOPARTICLES FOR THE DETECTION OF PROSTATE CANCER BIOMARKER KLK2

Prostate cancer (PCa) is the second most common cancer affecting the male population globally [1, 2]. Printed electrochemical sensors are widely used to detect and quantify PCa biomarkers, since they are easy to prepare, have high sensitivity, selectivity, and low cost [3]. In this study, an electrochemical immunosensor printed with graphite-based ink, carbon black, nail polish, and polyethylene terephthalate (PET) support was developed. The working electrode was modified with gold nanoparticles, antibodies, and bovine serum albumin (BSA) for the detection and quantification of KLK2 (human kallikrein 2). The parameters optimized for the best performance of the immunosensor were: antibody incubation time (40 min), BSA (30 min, 1.5 mg.mL^-1), antigen (60 min), pH and concentration of the supporting electrolyte (pH 7.5, 0.01 mol. L⁻¹). The study of the electrochemical behavior of the immunosensor was monitored by reducing the current signal of the potassium ferrocyanide redox probe, using the differential pulse voltammetry technique. With each decrease in the current, it was possible to prove the effectiveness of KLK2 immobilization and detection. The proposed immunosensor had an LOD of 0.17 ng.mL⁻¹ and an LOQ of 0.55 ng.mL⁻¹. Therefore, the results obtained suggest potential application of the immunosensor in real samples.