Electrochemical immunoplatform for the quantification of epithelial extracellular vesicles applied to prostate cancer diagnosis

Introduction: Prostate cancer (PCa) represents the second most commonly diagnosed cancer in men worldwide. This cancer is the most frequently diagnosed and the third cause of cancer-related deaths [1-3]. It is of vital importance to diagnose this cancer early to implement an effective treatment [4-5]. The present work reports an electrochemical immunoplatform based on magnetic microbeads (MBs) to determine epithelial extracellular vesicles (EpEVs) applied to PCa diagnosis.

Methods: Our method employs magnetic microparticles (MBs) as an immobilization platform. In an immune-electrochemical system, MBs enhance sensitivity through efficient capturing, analyte concentration, and easy washing in the presence of an external magnetic field. So far, no reported proposed sensor has been developed to detect EpCAM + extracellular vesicles (EVs) in diagnosing PCa. Hence, we report an electrochemical sandwich-type bioassay for assessing EpCAM + EVs in the early stages of PCa. Through the immobilization of the capture antibody (monoclonal anti-EpCAM) on HOOC-MBs, its incubation with EVs and a specific biotinylated detector antibody (anti-CD81) labeled with a streptavidin horseradish peroxidase (strep-HRP) polymer are observed. The amperometric detection of the affinity reaction was performed using disposable screen-printed carbon electrodes (SPCEs) and the hydroquinone (HQ)/H₂O₂ system.

Results: The detection limits for the proposed method and the ELISA test were 0.4 ng µL⁻¹ and 5 ng µL⁻¹, and the intra- and inter-assay coefficients of variation were below 3.81% and 6.54%, respectively.

Conclusions: Our electrochemical immunoplatform offers an interesting analytical tool for PCa diagnosis and prognostics.

References:

[1] doi: 10.3322/CAAC.21660.

[2] doi: 10.1002/IJC.29538.

[3] doi: 10.1016/J.EUF.2015.01.002.

[4] doi: 10.1016/J.BIOS.2017.11.029.

[5] doi: 10.1007/S00604-019-3410-0.