Disposable paper-based screen-printed electrochemical immunoplatform for dual detection of esophageal cancer biomarkers in patients' serum samples

Esophageal cancer is an aggressive disease with an extremely poor prognosis. However, early detection and timely treatment improve the chances of survival. Therefore, in this study, disposable, low-cost, flexible, reagentless, and highly sensitive paper-based screen-printed electrochemical immunosensors were developed for the dual determination of cytokeratin fragment 21-1 (CYFRA-21-1) and tumor protein (TP53) biomarkers in patient serum samples. For this, graphite ink was prepared with the help of a screen-printing machine, a in homepaper-based screen-printed electrode (SPE) substrate was fabricated on its surface. The immobilization of antibodies (CYFRA21-1 and TP53, individually) and BSA were done on inhome paper-based SPE directly using the drop-cast method. The paper-based SPE and other immunoelectrodes were characterized using Fourier transform infrared (FT-IR) spectroscopy, contact angle, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectroscopy. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were employed as electrochemical methods for evaluating the performances of immunoplatforms. Under the optimized conditions, the immunoplatforms exhibited a wide linear range for CYFRA21-1 and TP53 from 0.1 to 25 ng mL-1 and 0.001-10 ng mL-1, respectively. Comparatively, TP53 showed better results in terms of sensitivity [222.62 mu A (log10 ng mL-1 cm-2)-1], the limit of quantification (LOQ) [0.018 ng mL-1], and the limit of detection (LOD) [0.005 ng mL-1] in contrast to CYFRA21-1 (sensitivity, 167.07 mu A (log10 ng mL-1 cm-2)-1; LOQ, 0.041 ng mL-1; and LOD, 0.012 ng mL-1). Thus, the developed immunosensors could potentially be applied as biodevices in clinical laboratories or employed for detecting cancer biomarkers in different human fluids since this method is sensitive, uncomplicated, affordable, portable, and straightforward to develop. A schematic illustration of the fabrication of disposable paper-based screen-printed electrochemical immunoplatforms for dual detection of esophageal cancer biomarkers in patient serum samples.