Disposable electrochemical immunosensor for prostate cancer detection

Prostate cancer (PCa) is the second most common cancer amongst men worldwide; hence its early and accurate diagnosis is crucial. Due to the lacking current diagnostic approaches, an urgent need arises for an alternating analytical platform targeting selective PCa biomarkers while testing in body fluids, such as urine and serum. With this motivation, we established a disposable and label-free electrochemical immunosensor for sensitive detection of the selective PCa biomarker, prostate-specific membrane antigen (PSMA). A screen-printed gold electrode (SPGE), with its working electrode functionalized by cysteamine-modified gold nanoparticles (Cys-AuNPs), served as the sensor platform. The PSMA was detected by introducing PSMA protein/PSMA-expressing PCa cells with various concentrations and performing differential pulse voltammetry (DPV) measurements. The established biosensor has detection limits of 0.47 ng/mL for PSMA proteins (0-5 ng/mL range) and 5 cells/mL (0-100 cells/mL range) for PSMA-expressing PCa cells. The corresponding limit of quantification (LOQ) and detection sensitivities were calculated as 2.20 ng/mL and 4 cells/mL; 1.71 mu A.mL/ng and 0.15 mu A.mL/cell, respectively. The selectivity studies confirmed that the DPV signals exerted by PSMA (+) cells were statistically significant in comparison to the PSMA (-) groups (p = 0.012, p * < 0.05). The developed immunosensor platform offers a feasible alternative to facilitate PCa diagnosis. Also, to the best of our knowledge, it displayed the highest analytical performance for PSMA-expressing PCa cells detection amongst its peers. Therefore, it can be adapted for different proteins, particularly for cell detection, to facilitate other types of cancerous cells' diagnosis soon.