Ultrasensitive Electrochemical Diagnostic Platform for Dual Cancer Biomarkers Using a Disposable Sheet@Polymer Nanocomposite-Based Screen-Printed Electrode

In this work, two-dimensional tungsten disulfide (WS₂) nanosheets and polyaniline (PANI) as WS₂@PANI nanocomposites were used for constructing an electrochemical immunosensor for dual ovarian cancer biomarker detection, i.e., cancer antigen-125 (CA-125) and human epididymis protein 4 (HE4). A disposable screen-printed electrode (SPE) substrate, composed of graphite conductive ink, served as a platform onto which WS₂@PANI was deposited. The WS₂@PANI-modified SPE surface was further functionalized by immobilizing EDC:NHS-activated antibodies (ab-CA-125 and ab-HE4), followed by treatment with 1% bovine serum albumin (BSA) protein to block nonspecific binding sites. Further, the electrochemical performance of the fabricated immunoelectrodes, ab-CA-125/WS₂@PANI/SPE and ab-HE4/WS₂@PANI/SPE, was evaluated by a cyclic voltammetry (CV) technique. These modified immunoelectrodes demonstrated excellent detection capabilities for dual cancer biomarkers, with CA-125 detected in the concentration range from 0.0001 to 40 μg/mL and the HE4 detection range being 0.0001–500 ng/mL, respectively. The dual electrochemical biosensing system for CA-125 biomarkers demonstrated a high sensitivity of 85.28 μA/(μg/mL)/cm² with a low limit of detection (LOD) of 10 pg/mL. Similarly, the HE4 biomarker exhibited a sensitivity of 76.71 μA/(ng/mL)/cm² with an LOD of 15 fg/mL. The fabricated biosensing platform was further validated by serum samples of ovarian cancer patients, yielding results within the acceptable ranges, including %RSD and %recovery. Therefore, these findings underscore the potential of the WS₂@PANI-based biosensing platform for highly sensitive, selective, and reliable dual cancer biomarker detection, positioning it as a promising tool for clinical cancer diagnostics.